diff --git a/src/bub/builtin/store.py b/src/bub/builtin/store.py
index 9c91753d..0a2a1ea3 100644
--- a/src/bub/builtin/store.py
+++ b/src/bub/builtin/store.py
@@ -301,7 +301,7 @@ def append(self, entry: TapeEntry) -> None:
             self._read_locked()
             with self.path.open("a", encoding="utf-8") as handle:
                 next_id = self._next_id()
-                stored = TapeEntry(next_id, entry.kind, dict(entry.payload), dict(entry.meta))
-                handle.write(json.dumps(asdict(entry), ensure_ascii=False) + "\n")
+                stored = TapeEntry(next_id, entry.kind, dict(entry.payload), dict(entry.meta), entry.date)
+                handle.write(json.dumps(asdict(stored), ensure_ascii=False) + "\n")
                 self._read_entries.append(stored)
                 self._read_offset = handle.tell()
diff --git a/tests/test_file_tape_store_entry_ids.py b/tests/test_file_tape_store_entry_ids.py
new file mode 100644
index 00000000..15d50baf
--- /dev/null
+++ b/tests/test_file_tape_store_entry_ids.py
@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+import pytest
+from republic import TapeEntry
+
+from bub.builtin.store import FileTapeStore, ForkTapeStore
+
+
+@pytest.mark.asyncio
+async def test_file_tape_store_assigns_monotonic_ids_when_merging_forked_entries(tmp_path) -> None:
+    parent = FileTapeStore(directory=tmp_path)
+    store = ForkTapeStore(parent)
+
+    async with store.fork("tape", merge_back=True):
+        await store.append("tape", TapeEntry.event(name="first", data={"n": 1}))
+
+    async with store.fork("tape", merge_back=True):
+        await store.append("tape", TapeEntry.event(name="second", data={"n": 2}))
+
+    entries = parent.read("tape") or []
+    assert [entry.id for entry in entries] == [1, 2]
+    assert [entry.payload.get("name") for entry in entries] == ["first", "second"]