diff --git a/synapse/storage/util/sequence.py b/synapse/storage/util/sequence.py
index 2ea1de4bfa..fbfa30b489 100644
--- a/synapse/storage/util/sequence.py
+++ b/synapse/storage/util/sequence.py
@@ -44,9 +44,9 @@
 https://github.com/matrix-org/synapse. Please include the following data with
 your report:
 -----
-last_value: '%(last_value)',    is_called: '%(is_called)',
-max_stream_id: '%(max_stream_id)',
-max_in_stream_positions: '%(max_in_stream_positions)'
+last_value: '%(last_value)s',    is_called: '%(is_called)s',
+max_stream_id: '%(max_stream_id)s',
+max_in_stream_positions: '%(max_in_stream_positions)s'
 -----
 
 A temporary workaround to fix this error is to shut down Synapse (including
diff --git a/tests/server.py b/tests/server.py
index d17b2478e3..001d11e5e8 100644
--- a/tests/server.py
+++ b/tests/server.py
@@ -387,7 +387,7 @@ def make_request(
         shorthand: Whether to try and be helpful and prefix the given URL
             with the usual REST API path, if it doesn't contain it.
         federation_auth_origin: if set to not-None, we will add a fake
-            Authorization header pretenting to be the given server name.
+            Authorization header pretending to be the given server name.
         content_type: The content-type to use for the request. If not set then will default to
             application/json unless content_is_form is true.
         content_is_form: Whether the content is URL encoded form data. Adds the
diff --git a/tests/storage/test_id_generators.py b/tests/storage/test_id_generators.py
index 051c5de44d..cae00c3ba7 100644
--- a/tests/storage/test_id_generators.py
+++ b/tests/storage/test_id_generators.py
@@ -30,13 +30,14 @@
 from synapse.storage.types import Cursor
 from synapse.storage.util.id_generators import MultiWriterIdGenerator
 from synapse.storage.util.sequence import (
+    _INCONSISTENT_STREAM_ERROR,
     LocalSequenceGenerator,
     PostgresSequenceGenerator,
     SequenceGenerator,
 )
 from synapse.util.clock import Clock
 
-from tests.unittest import HomeserverTestCase
+from tests.unittest import HomeserverTestCase, TestCase
 from tests.utils import USE_POSTGRES_FOR_TESTS
 
 
@@ -789,3 +790,28 @@ def test_load_existing_stream(self) -> None:
         self.assertEqual(second_id_gen.get_current_token_for_writer("first"), 7)
         self.assertEqual(second_id_gen.get_current_token_for_writer("second"), 7)
         self.assertEqual(second_id_gen.get_persisted_upto_position(), 7)
+
+
+class InconsistentStreamErrorFormatTest(TestCase):
+    """Test that _INCONSISTENT_STREAM_ERROR can be formatted without raising a
+    ValueError.
+    """
+
+    def test_format_with_all_parameters(self) -> None:
+        params = {
+            "seq": "events_sequence",
+            "stream_name": "events",
+            "last_value": 42,
+            "is_called": True,
+            "max_stream_id": 50,
+            "max_in_stream_positions": 55,
+        }
+
+        result = _INCONSISTENT_STREAM_ERROR % params
+
+        self.assertIn("events_sequence", result)
+        self.assertIn("events", result)
+        self.assertIn("42", result)
+        self.assertIn("True", result)
+        self.assertIn("50", result)
+        self.assertIn("55", result)
diff --git a/tests/unittest.py b/tests/unittest.py
index 79251cd76c..0220548d7b 100644
--- a/tests/unittest.py
+++ b/tests/unittest.py
@@ -604,7 +604,7 @@ def make_request(
             shorthand: Whether to try and be helpful and prefix the given URL
             with the usual REST API path, if it doesn't contain it.
             federation_auth_origin: if set to not-None, we will add a fake
-                Authorization header pretenting to be the given server name.
+                Authorization header pretending to be the given server name.
 
             content_type: The content-type to use for the request. If not set then will default to
                 application/json unless content_is_form is true.