Since I zero the Z axis regularly, I likely hit the y or x by mistake and that would explain what happened. Its amazing that I have not done that before in many years of use. I set it up initially and have never touched it since. I use the G54 offset to define my 0,0 to be in the front left hand corner. It was easy enough to redo it by just moving to the soft limits in that corner and then re-zeroing the X and Y axis's.
Since I never normally rezero the x and y axis's, I normally don't even regen the paths and everything still works fine.