Traktor BPM jumping

Ok, i may get crushed for this question, b/c it sounds like something simple but, in the event it is something simple, i figured i would throw it out there. I usually dj using deck a or b as the master (i don't usually sync to the master clock). At my weekly gig this past Wednesday I started having this weird issue where A and B would be synced up with either one being the master, and the BPM kept jumping up or down, bringing the pitch back to +-0 on its own (ie, if the pitch was +3 it would travel on its own to 0; if it was -3 it would slide on its own back to 0). I would move the pitch back where i wanted it, it would stay there for a few seconds, then it would ghost move back to 0. eventually i just set the master clock at the bpm i wanted and sync'd to that and had no problems after that. Pretty weird since i had been djing the same way for months with no such issues. I'm sure this is something simple that i'm just missing. Has anyone had a similar issue, or happens to know the fix? Many thanks for any input.