diff --git a/anki/collection.py b/anki/collection.py
index acf151647..03b5c9eaf 100644
--- a/anki/collection.py
+++ b/anki/collection.py
@@ -937,4 +937,4 @@ and type=0""", [intTime(), self.usn()])
     def setUserFlag(self, flag, cids):
         assert 0 <= flag <= 7
         self.db.execute("update cards set flags = (flags & ~?) | ?, usn=?, mod=? where id in %s" %
-                        ids2str(cids), 0b111, flag, self._usn, intTime())
+                        ids2str(cids), 0b111, flag, self.usn(), intTime())