The problem I had was that when Garageband was open and I was playing my movie in Premiere, the sound was slower and it was jumpy. When I closed Garageband, it was fixed. The problem I’m having now is that one of the files I imported from GB won’t even play, unless nothing else is playing with it. (i.e., a voice over)
And all extra audio files have to be on track 7, don’t know why. The GB file plays on track 7 too, as it is by itself there.