Reply to pitch slider / traktor tempo going crazy at gig

hey, not the biggest deal, but had a crazy gig last evening and i noticed my left tempo (deck 1) was going nuts in traktor, like it was being jittered / nudged micro amounts up and down. there was a monitor sub right next to it, do you guys believe the bass could have been affecting the pitch slider causing this crazy jitter? i can't recreate the problem when not on stage with lots of club bass.... just wonderin. thanks!