Boom mic visible: Directly after the first rendition of "Going My Way", the shadow of the boom mic can be seen moving on the church wall behind father Fitzgibbon and Miss Linden.
Audio/visual unsynchronized: Obvious lip syncing during "Going My Way".
Continuity: When Father O'Malley is talking to Jenny while she is getting ready to perform, the conductor can be seen taking out his cigarette case and opening it twice, in two adjacent shots.