Why are some older songs in an inbetween tuning. Like MJ's Smooth Criminal? https://youtu.be/_mMyPJSx8RU It's inbetween A and A#.
because of tapes. tapes can readily change the speed, which also changes the pitch. this can happen by accident, or, in some cases it can be done on purpose, for a last-minute tempo adjustment without having to re-record the song