Wanted to post this in case it helps someone. After doing a successful print, and tweaking my design a bit, i attempted to do another print but it kept failing. Tried the usual turn off/on dance, but calibration seemed to be stuck in a loop, with the head moving back and forth between two points.
While waiting it out to see if it righted itself, I scanned the boards and found a reply on one thread that questioned if there was a big window close by, if so the sun may be screwing with the camera. Since I have sun streaming in right on my GF i decided to try closing the blinds, and voila! calibration continues smoothly.