ddj-rb reverse roll is off beat, only on one side!

how weird is that? the right hand side works fine, it's perfectly on beat, with or without quantize on, any track, no problems. left hand side? it acts like it can't find the beat, starts half-step off, like on the high hat, instead of the kick. doesn't matter when i hit it, starts all wrong, and then it starts out in like 1/2 time even though it's on 1/1, but then it slows down. makes no sense whatsoever. tried it with the sync on, and then it syncs but it's perfectly synced to a half-step off, it won't sync to the kick. so bizarre! anybody have a guess?