diff --git a/packages/super-editor/src/extensions/track-changes/trackChangesHelpers/replaceStep.js b/packages/super-editor/src/extensions/track-changes/trackChangesHelpers/replaceStep.js
index a9a0f65825..5c40536ed7 100644
--- a/packages/super-editor/src/extensions/track-changes/trackChangesHelpers/replaceStep.js
+++ b/packages/super-editor/src/extensions/track-changes/trackChangesHelpers/replaceStep.js
@@ -40,16 +40,33 @@ export const replaceStep = ({ state, tr, step, newTr, map, user, date, originalS
     }
   }
 
+  // When pasting into a textblock, try the open slice first so content merges inline
+  // instead of creating new paragraphs (prevents inserting block nodes into non-textblocks).
+  const baseParentIsTextblock = trTemp.doc.resolve(positionTo).parent?.isTextblock;
+  const shouldPreferInlineInsertion = step.from === step.to && baseParentIsTextblock;
+
   const tryInsert = (slice) => {
-    const insertionStep = new ReplaceStep(positionTo, positionTo, slice, false);
-    if (trTemp.maybeStep(insertionStep).failed) return null;
-    return {
-      insertedFrom: insertionStep.from,
-      insertedTo: insertionStep.getMap().map(insertionStep.to, 1),
-    };
+    const tempTr = state.apply(newTr).tr;
+    // Empty slices represent pure deletions (no content to insert).
+    // Detecting them ensures deletion tracking runs even if `tempTr` doesn't change.
+    const isEmptySlice = slice?.content?.size === 0;
+    try {
+      tempTr.replaceRange(positionTo, positionTo, slice);
+    } catch {
+      return null;
+    }
+
+    if (!tempTr.docChanged && !isEmptySlice) return null;
+
+    const insertedFrom = tempTr.mapping.map(positionTo, -1);
+    const insertedTo = tempTr.mapping.map(positionTo, 1);
+    if (insertedFrom === insertedTo) return { tempTr, insertedFrom, insertedTo };
+    if (shouldPreferInlineInsertion && !tempTr.doc.resolve(insertedFrom).parent?.isTextblock) return null;
+    return { tempTr, insertedFrom, insertedTo };
   };
 
-  const insertion = tryInsert(step.slice) || tryInsert(Slice.maxOpen(step.slice.content, true));
+  const openSlice = Slice.maxOpen(step.slice.content, true);
+  const insertion = tryInsert(step.slice) || tryInsert(openSlice);
 
   // If we can't insert the replacement content into the temp transaction, fall back to applying the original step.
   // This keeps user intent (content change) even if we can't represent it as tracked insert+delete.
@@ -61,16 +78,22 @@ export const replaceStep = ({ state, tr, step, newTr, map, user, date, originalS
   }
 
   const meta = {};
-  const insertedMark = markInsertion({
-    tr: trTemp,
-    from: insertion.insertedFrom,
-    to: insertion.insertedTo,
-    user,
-    date,
-  });
+  const { insertedFrom, insertedTo, tempTr } = insertion;
+  let insertedMark = null;
+  let trackedInsertedSlice = Slice.empty;
+
+  if (insertedFrom !== insertedTo) {
+    insertedMark = markInsertion({
+      tr: tempTr,
+      from: insertedFrom,
+      to: insertedTo,
+      user,
+      date,
+    });
+    trackedInsertedSlice = tempTr.doc.slice(insertedFrom, insertedTo);
+  }
 
   // Condense insertion down to a single replace step (so this tracked transaction remains a single-step insertion).
-  const trackedInsertedSlice = trTemp.doc.slice(insertion.insertedFrom, insertion.insertedTo);
   const condensedStep = new ReplaceStep(positionTo, positionTo, trackedInsertedSlice, false);
   if (newTr.maybeStep(condensedStep).failed) {
     // If the condensed step can't be applied, fall back to the original step and skip deletion tracking.
@@ -86,7 +109,7 @@ export const replaceStep = ({ state, tr, step, newTr, map, user, date, originalS
   const mirrorIndex = map.maps.length - 1;
   map.appendMap(condensedStep.getMap(), mirrorIndex);
 
-  if (insertion.insertedFrom !== insertion.insertedTo) {
+  if (insertedFrom !== insertedTo) {
     meta.insertedMark = insertedMark;
     meta.step = condensedStep;
     // Store the actual insertion end position for cursor placement (SD-1624).
@@ -94,13 +117,13 @@ export const replaceStep = ({ state, tr, step, newTr, map, user, date, originalS
     // For single-step transactions, positionTo is in newTr.doc coordinates after our condensedStep,
     // so we just add the insertion length to get the cursor position.
     if (positionAdjusted) {
-      const insertionLength = insertion.insertedTo - insertion.insertedFrom;
+      const insertionLength = insertedTo - insertedFrom;
       meta.insertedTo = positionTo + insertionLength;
     }
   }
 
-  if (!newTr.selection.eq(trTemp.selection)) {
-    newTr.setSelection(trTemp.selection);
+  if (!newTr.selection.eq(tempTr.selection)) {
+    newTr.setSelection(tempTr.selection);
   }
 
   if (step.from !== step.to) {
diff --git a/packages/super-editor/src/extensions/track-changes/trackChangesHelpers/replaceStep.test.js b/packages/super-editor/src/extensions/track-changes/trackChangesHelpers/replaceStep.test.js
index 929d322b2d..86704c5db1 100644
--- a/packages/super-editor/src/extensions/track-changes/trackChangesHelpers/replaceStep.test.js
+++ b/packages/super-editor/src/extensions/track-changes/trackChangesHelpers/replaceStep.test.js
@@ -1,5 +1,6 @@
 import { beforeEach, afterEach, describe, expect, it, vi } from 'vitest';
 import { EditorState, TextSelection } from 'prosemirror-state';
+import { DOMParser as PMDOMParser, Slice } from 'prosemirror-model';
 import { trackedTransaction, documentHelpers } from './index.js';
 import { TrackInsertMarkName, TrackDeleteMarkName } from '../constants.js';
 import { TrackChangesBasePluginKey } from '../plugins/trackChangesBasePlugin.js';
@@ -207,6 +208,169 @@ describe('trackChangesHelpers replaceStep', () => {
     expect(insertedText).toBe('xy');
   });
 
+  it('tracks single-paragraph HTML paste insertions', () => {
+    const doc = schema.nodes.doc.create(
+      {},
+      schema.nodes.paragraph.create({}, schema.nodes.run.create({}, [schema.text('Base')])),
+    );
+    let state = createState(doc);
+
+    const basePos = findTextPos(state.doc, 'Base');
+    expect(basePos).toBeTypeOf('number');
+    const insertPos = basePos + 'Base'.length;
+    state = state.apply(state.tr.setSelection(TextSelection.create(state.doc, insertPos)));
+
+    const tempDiv = document.createElement('div');
+    tempDiv.innerHTML = '<p>Paste One</p>';
+    const parsedDoc = PMDOMParser.fromSchema(schema).parse(tempDiv);
+    const slice = new Slice(parsedDoc.content, 0, 0);
+
+    let tr = state.tr.replaceSelection(slice);
+    tr.setMeta('inputType', 'insertFromPaste');
+    const tracked = trackedTransaction({ tr, state, user });
+    const finalState = state.apply(tracked);
+
+    let insertedText = '';
+    finalState.doc.descendants((node) => {
+      if (node.isText && node.marks.some((mark) => mark.type.name === TrackInsertMarkName)) {
+        insertedText += node.text;
+      }
+    });
+
+    expect(insertedText).toContain('Paste One');
+  });
+
+  it('tracks multi-paragraph HTML paste insertions', () => {
+    const doc = schema.nodes.doc.create(
+      {},
+      schema.nodes.paragraph.create({}, schema.nodes.run.create({}, [schema.text('Base')])),
+    );
+    let state = createState(doc);
+
+    const basePos = findTextPos(state.doc, 'Base');
+    expect(basePos).toBeTypeOf('number');
+    const insertPos = basePos + 'Base'.length;
+    state = state.apply(state.tr.setSelection(TextSelection.create(state.doc, insertPos)));
+
+    const tempDiv = document.createElement('div');
+    tempDiv.innerHTML = '<p>Paste One</p><p>Paste Two</p>';
+    const parsedDoc = PMDOMParser.fromSchema(schema).parse(tempDiv);
+    const slice = new Slice(parsedDoc.content, 0, 0);
+
+    let tr = state.tr.replaceSelection(slice);
+    tr.setMeta('inputType', 'insertFromPaste');
+    const tracked = trackedTransaction({ tr, state, user });
+    const finalState = state.apply(tracked);
+
+    let insertedText = '';
+    finalState.doc.descendants((node) => {
+      if (node.isText && node.marks.some((mark) => mark.type.name === TrackInsertMarkName)) {
+        insertedText += node.text;
+      }
+    });
+
+    expect(insertedText).toContain('Paste One');
+    expect(insertedText).toContain('Paste Two');
+  });
+
+  it('tracks plain-text paste insertions', () => {
+    const doc = schema.nodes.doc.create(
+      {},
+      schema.nodes.paragraph.create({}, schema.nodes.run.create({}, [schema.text('Base')])),
+    );
+    let state = createState(doc);
+
+    const basePos = findTextPos(state.doc, 'Base');
+    expect(basePos).toBeTypeOf('number');
+    const insertPos = basePos + 'Base'.length;
+    state = state.apply(state.tr.setSelection(TextSelection.create(state.doc, insertPos)));
+
+    let tr = state.tr.insertText('Plain Paste', insertPos);
+    tr.setMeta('inputType', 'insertFromPaste');
+    const tracked = trackedTransaction({ tr, state, user });
+    const finalState = state.apply(tracked);
+
+    let insertedText = '';
+    finalState.doc.descendants((node) => {
+      if (node.isText && node.marks.some((mark) => mark.type.name === TrackInsertMarkName)) {
+        insertedText += node.text;
+      }
+    });
+
+    expect(insertedText).toContain('Plain Paste');
+  });
+
+  it('tracks paste replacement over selected existing text', () => {
+    const doc = schema.nodes.doc.create(
+      {},
+      schema.nodes.paragraph.create({}, schema.nodes.run.create({}, [schema.text('Hello World')])),
+    );
+    let state = createState(doc);
+
+    const worldPos = findTextPos(state.doc, 'Hello World');
+    expect(worldPos).toBeTypeOf('number');
+    const from = worldPos + 'Hello '.length;
+    const to = from + 'World'.length;
+    state = state.apply(state.tr.setSelection(TextSelection.create(state.doc, from, to)));
+
+    const tempDiv = document.createElement('div');
+    tempDiv.innerHTML = '<p>Pasted</p>';
+    const parsedDoc = PMDOMParser.fromSchema(schema).parse(tempDiv);
+    const slice = new Slice(parsedDoc.content, 0, 0);
+
+    let tr = state.tr.replaceSelection(slice);
+    tr.setMeta('inputType', 'insertFromPaste');
+    const tracked = trackedTransaction({ tr, state, user });
+    const meta = tracked.getMeta(TrackChangesBasePluginKey);
+    const finalState = state.apply(tracked);
+
+    let insertedText = '';
+    let deletedText = '';
+    finalState.doc.descendants((node) => {
+      if (!node.isText) return;
+      if (node.marks.some((mark) => mark.type.name === TrackInsertMarkName)) insertedText += node.text;
+      if (node.marks.some((mark) => mark.type.name === TrackDeleteMarkName)) deletedText += node.text;
+    });
+
+    expect(insertedText).toContain('Pasted');
+    expect(deletedText).toContain('World');
+    expect(meta?.insertedMark).toBeDefined();
+    expect(meta?.deletionMark).toBeDefined();
+    expect(meta.insertedMark.attrs.id).toBe(meta.deletionMark.attrs.id);
+  });
+
+  it('prefers original paste slice before maxOpen fallback for collapsed insertions', () => {
+    const doc = schema.nodes.doc.create(
+      {},
+      schema.nodes.paragraph.create({}, schema.nodes.run.create({}, [schema.text('Base')])),
+    );
+    let state = createState(doc);
+
+    const basePos = findTextPos(state.doc, 'Base');
+    expect(basePos).toBeTypeOf('number');
+    const insertPos = basePos + 'Base'.length;
+    state = state.apply(state.tr.setSelection(TextSelection.create(state.doc, insertPos)));
+
+    const originalDiv = document.createElement('div');
+    originalDiv.innerHTML = '<p>Paste One</p><p>Paste Two</p>';
+    const originalSlice = new Slice(PMDOMParser.fromSchema(schema).parse(originalDiv).content, 0, 0);
+
+    const fallbackDiv = document.createElement('div');
+    fallbackDiv.innerHTML = '<p>Flattened Fallback</p>';
+    const fallbackSlice = new Slice(PMDOMParser.fromSchema(schema).parse(fallbackDiv).content, 0, 0);
+    vi.spyOn(Slice, 'maxOpen').mockReturnValue(fallbackSlice);
+
+    let tr = state.tr.replaceSelection(originalSlice);
+    tr.setMeta('inputType', 'insertFromPaste');
+    const tracked = trackedTransaction({ tr, state, user });
+    const finalState = state.apply(tracked);
+
+    const text = finalState.doc.textBetween(0, finalState.doc.content.size, '\n');
+    expect(text).toContain('Paste One');
+    expect(text).toContain('Paste Two');
+    expect(text).not.toContain('Flattened Fallback');
+  });
+
   it('tracks replace even when selection contains existing deletions and links', () => {
     const linkMark = schema.marks.link.create({ href: 'https://example.com' });
     const existingDeletion = schema.marks[TrackDeleteMarkName].create({