diff --git a/ruff.toml b/ruff.toml
index 3a4fb14..9d2413c 100755
--- a/ruff.toml
+++ b/ruff.toml
@@ -159,7 +159,7 @@ convention = "google"
 
 [lint.per-file-ignores]
 "tests/fixtures/sample_type_aliases.py" = [
-  "UP040", # Type alias uses `TypeAlias` annotation instead of the `type` keyword
+  "UP040", # Intentionally using TypeAlias for backwards compatibility testing
 ]
 "tests/*.py" = [
   "ANN",
diff --git a/tests/test_snapshot.py b/tests/test_snapshot.py
index 17039e9..3cc2e17 100644
--- a/tests/test_snapshot.py
+++ b/tests/test_snapshot.py
@@ -147,3 +147,12 @@ def test_read_manifest_returns_none_on_invalid_types(self, manager):
         # Should be a dict, not a list
         manager.manifest_path.write_text("[]", encoding="utf-8")
         assert manager.read_manifest() is None
+
+    def test_read_manifest_returns_none_on_invalid_entry_format(self, manager):
+        manager.snapshot_dir.mkdir(parents=True, exist_ok=True)
+        # Entry missing required keys will raise TypeError in SnapshotEntry(**e)
+        manager.manifest_path.write_text(
+            '{"timestamp": "2024-01-01T00:00:00Z", "entries": [{"invalid_key": "value"}]}',
+            encoding="utf-8",
+        )
+        assert manager.read_manifest() is None