Tempo change ruining song

Hey all - I’m not entirely sure how to describe what is going on… I have begun recording a song, it currently has 6 tracks.

I started it yesterday - at 110 bpm and set to “keep” tempo.

I haven’t adjusted tempo at all.

I saved it a couple times along the way.

I left logic open overnight and when I went in to listen to it today (through speakers rather than headphones) - the tempo of the individual tracks has changed… meaning the chord changes don’t line up, the drums and vocals are off, etc.

It’s at most 10bpm. Enough to make it noticeable… but I’m very confused as to what happened

(this is the second time it has happened, the first time I thought it may have been something I did and scrapped the project entirely)

Any ideas what could be going on?!?