I just learned that if you move the head manually while putting your material on the bed, the Glowforge has NO IDEA that you did this. It proceeds to cut on the assumption the head is starting where it had been parked.
I sent a job where it should cut a circle in the middle of the bed, and fortunately my accidental offset was JUST barely not enough to drive me out of the cutting area (I wound up charring my rubber flap for the passthrough, don’t think I actually cut through it)
You can see here the red circle where the glowforge THOUGHT it was going to cut, and the char outlined circle far below where it actually did cut.
I can turn the machine off and on to force a calibration (what I did after this job), but having a button somewhere in the App to force a calibration (maybe even a shorter one for just re-home) would be desired.