I’d completely forgotten about it, but mine did that once too, for the same reason. Those wheels can jump the track if the path is blocked down at tray level. (Think I was trying to squeeze in an end cut onto the cutting area on the opposite side.)
It can also jump off the track if you’re trying to move the head past something too tall…that cow-catcher on the air assist can hit something and bounce. (foam-core)
Don’t think I ever contacted support about either incident though, it was clear what happened, and I just turned off the machine, put it back, and went back to cutting.
Might not be what happened here, and speculating does nobody any good, but if you contacted support they can walk through what’s going on with you. The gantry is designed to move up and down a little bit.