I’ll post some pics of the electronics.
I did check all the connections but I have all my steppers soldered and shrink wrapped so I’ll have to unsolder I guess to check each one.
Here’s a strange development that may be a clue. My max speeds set in the usb cnc software is 4800 but I usually jog at 3600. On a desperate attempt I set the max speed down to 2800. And now the problem has yet to reappear. That’s a horrible solution of course and I’m running a simple bed leveling gcode now to see if it looses steps.
I should say my driver boards have stick on heat sinks and get pretty hot. As do my steppers. I of course have consider that the motors could just be cooked or drivers or both and that the timing was completely unrelated