This happens on both of my ender 3s, they both have a CR touch. one has a 4.2.7 and the other has a 4.2.2 board. when running the g29 command through pronterface it will most of the time successfully probe the bed. some of the time it will just crash the print head into the bed and continue moving down, some of the time it will just stop and say failed. both have firmware from the builder made within the last month.
Hello! I had the same issue as you did. My machine that was doing the same thing was Ender 3 V2, board 4.2.7. It had stock firmware on it and would crash the print head randomly or error.
I upgraded firmware to Marlin:
Ender3-v2-v427-BLTouch-MarlinUI-20231003.bin (main board) and
All of the crashing issues disappeared.
Note: if you have filament runout sensor, make sure it is a digital encoder type and not just a momentary switch type. If you have only the momentary switch type. disable it in user interface of the printer.
I am still having this issue, I was wondering if there is a different fix for this. It runs OK a few times then crashes into the bed and Reset display comes up. Sometimes, I have to watch the printing and if the needle doesn’t drop down, I hit the OctoPrint emergency stop, then have to reset the machine. Mine is a V1 and have the latest version installed for the BLTouch