Audio problem: When Tim enters Gordon's office, you hear Tim greeting Barbara, but it is Barbara's mouth that is moving. When Barbara replies, her mouth isn't moving.
Batman Beyond: Return of the Joker (2000)
1 audio problem
Directed by: Curt Geda
Starring: Mark Hamill, Kevin Conroy, Dean Stockwell, Teri Garr, Will Friedle, Angie Harmon
Continuity mistake: When Bruce plays the clip of the Joker appearing at the rooftop party, the audio clip that plays with it is not the same as when the Joker actually said it during the attack. The clip seems a bit more subdued than the actual voice track.
Batman: He's tough. Any suggestions, boss?
Bruce Wayne: Joker's vain and likes to talk, he'll try to distract you, but don't listen. Block it out and power on through.
Batman: Wait... I like to talk, too.
Trivia: In the original version, Tim does not throw the gun down. He shoots it at the Joker, who dies when he's impaled with a flag shooting out the gun reading, "Bang".