This just happened to me. Note that my layer number and time are exact, as I have Home Assistant integration that recorded the progress. Stopping at 255 is very suspect, as that’s the max value of an 8-bit integer. Additionally, unlike all other prints where the “current layer” sensor stays on the end-layer of a finished print, the sensor returned to 0 after the alleged cancel.
Stock SD card: Yes
Bambu Lab Slicer Version: 01.10.1.50
P1 Firmware version: 01.07.00.00
ACTUAL Layer number where it failed: 255/812
ACTUAL Time elapsed between print start and failure: 2 hours, 5 mins