Quote Originally Posted by BLKKROW View Post
I do have an aluminum Y bed so I don't believe it is warping.

I also recently installed PID auto tune for the bed.
Hmm not sure then, the only time I had an issue like that was due to the wooden bed warping as I mentioned. You may double check your clearances on your rollers though just to make sure also make sure there was nothing else that could have gotten bound up and caused the Y belt to slip. Maybe also check your belt tension.