[RAMBo Rev 1.1 layer shifts- can large gcode files cause glitches? Dying board?]

From 2016-2020 I ran a Makergear M2 with a RAMBo V1.1, and it worked well for thousands of hours. 

 

Eventually I mothballed the printer- it had become very worn, and it started shifting along the X-axis on a specific 14-hour print. However now I'm building a CNC machine, and would love to use the board- assuming I can be certain it isn't going to glitch out on me again. Unexpected motor movements during a CNC operation can be pretty dangerous.

 

Additional details:

• The issue happened both when printing over USB and from SD
• The shifting happened on one specific print, a big highly textured dome. The print was a 61mb gcode file. I didn't check to see if it would happen on other large prints
  • Looking at other old gcode, most prints were smaller than this, but it appears I printed a 96mb file at least once without issue
• The shifting happened at random heights, and then would continue like normal
• The shifting was not caused by nozzle dragging. At one point I watched the shift happen- the print was happening like normal, then it suddenly shifted a few mm, and continued
  • It was circular, so the X and Y motors were always working. During the shift simultaneously the Y stepper would stop moving, and the X stepper would move the head outside the perimeter of the print
• This kind of problem had never happened in the thousands of hours of use prior, and I hadn't done any firmware/ slicer changes before it started happening
• Was running M2Marlinx1619V firmware

 

My best guesses are A) The board is failing after many hours of service or B) The board was somehow being freaked out by a large gcode file C) Some other thing I hadn't thought of

 

Does anyone know what the cause could be? Should I just bite the bullet and buy a new board?