diff --git a/files/helpers/sanitize.py b/files/helpers/sanitize.py
index f5e51d204..694495294 100644
--- a/files/helpers/sanitize.py
+++ b/files/helpers/sanitize.py
@@ -96,7 +96,7 @@ def execute_blackjack(v, target, body, kind):
 			extra_info = f"reports on {target.permalink}"
 		elif kind in {'comment', 'message'}:
 			for id in notified_ids:
-				existing = g.db.query(Notification).filter_by(comment_id=target.id, user_id=id)
+				existing = g.db.query(Notification).filter_by(comment_id=target.id, user_id=id).one_or_none()
 				if existing: continue
 				n = Notification(comment_id=target.id, user_id=id)
 				g.db.add(n)