Hi there, have this build for a while now. Recently i started having this issue, during my prints, the X axis stops for a heartbeat, then goes crazy both directions, very fast.
This happens sometimes during the first layers, some other times after 1 hour of printing. What i've tried so far:

Replaced the stepper driver for the X motor, didn't fix.
Replaced the X endstop, didn't fix.

Has anyone ever had this issue? Any feedback will be appreciated.

It might be the motor or the step sticks were hot, ever tried to touch the motor during operation? it's not recommended to touch the stepstick during operation though.

If it does hot, try to reduce the stepstick current

I solved it:

- The stepper driver was burning hot. I replaced all steppers, but the problem persisted. (Printing a closed cooling system for stepper drivers and mosfets).

- Replaced the motor. Problem persisted. (Later on i realised motor was also damaged).

- Replaced the RAMPS, problem fixed.

- Motor had problems when i used it in my other printer. Tried with different drivers and it doesn't rotate.

The reason for this problem to happen, i think, it might have to do with the overheating of components. I was not using any cooling over my eletronics (but truth be said, i've been using it like this for over a year). Problems started showing when i decided to heat up the bed another 10ºC (60 > 70) and some firmware misconfiguration wasn't shutting down the heatbed after printing was done. So i had the headbed on (and mosfet burning) for several hours.