How to reproduce:
Place a jukebox near a sitting parrot and place a disc in it
Break the jukebox / remove the disc
Now the parrot's upper body will or will not be misplaced depending on which part of the dancing animation it was in when the music was removed.
If the parrot's upper body is not misplaced, repeat.
How to fix:
Make one of the sitting parrots stand up.
Now all the parrots whose upper bodies were caused to be misplaced by the same jukebox as the parrot you made stand up, will have their upper bodies corrected to match the position of the legs.
Just noticed that when fixing my parrots, it is actually the upper body that is moved back to match the position of the legs, meaning it's the upper body that becomes misplaced, not the legs.