diff --git a/backend/pashub_fetcher/tests/test_core_files.py b/backend/pashub_fetcher/tests/test_core_files.py
index 2b20803c..e97df476 100644
--- a/backend/pashub_fetcher/tests/test_core_files.py
+++ b/backend/pashub_fetcher/tests/test_core_files.py
@@ -163,3 +163,14 @@ def test_core_file_for_unknown_filename_returns_none() -> None:
 
     # Assert
     assert result is None
+
+
+def test_core_file_for_osm_fallback_does_not_fire_when_evidence_category_present() -> None:
+    # Arrange — OSM+DR-N-A filename but evidence_category is something other than retrofit design
+    filename = "2512-OSM-H21M900-XX-DR-N-A_Lord Nelson Street 018.pdf"
+
+    # Act
+    result = core_file_for(filename, evidence_category="some other category")
+
+    # Assert
+    assert result is None