marker seems to move

hi everyone, happy new year i sure hope it's a good one.

this is strange, I always put my own start marker at the begiing of a song, usually after one bar of drums. what I've noticed is that the marker keeps moving a bit, not a lot and always later then where I put it, about a 1/16th note.

I know it's not my imagination because I've had to change it a lot. does anyone have any thoughts, ideas or anything else that might help.