Has that print been removed and cut at? It doesn’t look adhered to the surface and has a white border similar to how black ABS looks after cutting off a raft.
Disregarding that, I had something similar happen to me today, it was only on the first layer infill when I caught the cable, so quickly I heard the fan dip a bit but when I looked round the print head had moved over into the one of the corners, well away from the actual print, and started randomly carrying on the infill in the middle of nowhere, although it wasn’t cutting in to the PEI.
I’ve noticed that when you power off the machine quickly, after turning it back on until you actually home an axis the printer treats the position it was turned off at as home. Perhaps a rapid power surge/drop could have sent the printer a bit mad with nobody watching to correct it, although you’d have thought the Z stop would have prevented it from digging in like that, the only reason I could think it wouldn’t was if the bed was really out of level.