Yes actually I solved my issue awhile ago and forgot this was still posted. My z stop mount completely snapped off and I didn't realize it. I superglued it, printed a replacement, and then switched it. So very similar issue. Thank you for posting though! I hope this helps others with the same issue!

I have owned my M2 for 2 and a half years now and I have set the starting height and leveled the bed dozens of times. Recently I had a worn out filament drive which also resulted in a clogged nozzle. The nozzle has been unclogged and the drive replaced. Since I had to remove the hot end at one point...