This happened to me as well, didn’t plunge, but went totally off design. Tried a lot of different things to fix. None appeared to change anything, then I put the controller on a filtered UPS and the problem has never come back. When it happened, code checked out good. Wiring checked out good. Manual operation checked out good. System was used for several months prior without an issue. then during a simple waste-board leveling the machine went nuts. Have used the machine for several more months and no problems to date.