diff --git a/atlas/api.py b/atlas/api.py
index 0ff13b9d..8782f485 100644
--- a/atlas/api.py
+++ b/atlas/api.py
@@ -146,11 +146,8 @@ def upload_dicom(request, files: List[UploadedFile] = File(...)):
         except DuplicateDicom as e:
             duplicate.append((file.name, ud.image_blake3_hash))
 
-
-            if type(e.duplicate) == SeriesImage:
+            if isinstance(e.duplicate, SeriesImage) and e.duplicate.series is not None:
                 duplicate_series.add(e.duplicate.series.get_absolute_url())
-
-            pass
         except InvalidDicomError:
             failed.append(file.name)