anybody ever have a problem while the machine is running, it will "automatically" switch itself into MDI or sometimes JOG mode? none touches the machine it does it all its own, like a ghost is pushing the button. there are no alarms it just stops running and I will go back and press "memory" or auto and it will continue along sometimes for a while other time only a few minutes, then it does it again. really frustrating as we have a long running program (17 hours) and we leave the machine over night to run only to come in and find it had halted operation hours before.
the control is Fanuc 18I MB control.

any suggestions appreciated.

thanks, in advance.