The Wax Max - S3-E20
Revealing mistake: In the tunnel of Love scene, one shot shows an axe being thrust down at Max. The axe is visibly blunt.
The Wax Max - S3-E20
Visible crew/equipment: When an arrow is fired at the boat in the Tunnel of Love scene, the wire attached to it is visible.
Witness for the Persecution - S3-E3
Plot hole: In this episode, the villain makes a phone call to KAOS headquarters when he's captured demanding that they kill Max to stop him testifying in court against him. Later, several say that Max is the only witness to the villain's crimes, but the Chief and 99 were in the room when the villain made the call, so they could have been witnesses to "conspiracy to commit murder."
The Little Black Book: Part 1 - S3-E16
Audio problem: When Max is fighting the waiter, several times he misses the waiter completely, but you can still hear the sound.