General Protection fault (GPF) Ultra 2 hangs unresponsive

i've had my readynas for over a year, and it has been rock solid, plugged in and working every single day without issue until a couple weeks ago when i first noticed it was unresponsive. i, too, had to resort to doing a forced reset by holding the power button and then it stayed alive for a few days before happening again. it's now happened 3-4 times. i have not upgraded the firmware or made ANY changes at all prior to this happening. the logs show the similar "general protection fault" errors related to what looks like processes "empty_exim" and "exim". again, i made no recent changes, it just started happening and sounds all too familiar with other people's sudden incidents of same.