I did not, but yesterday I put marlin on the stock board (the first one to start doing the temp thing), and it's doing the same thing, so the pi isn't the problem.
I also tested the printer's power supply with my multimeter and it's stable between 23.8v-24.2v.
My house electricity is a little dodgy, my lights flicker for a half second when a high draw appliance turns on (AC, refrigerator, etc), but nothing in the house has ever been damaged by it in the 5 years I've been here, so I don't think it's strong enough to kill multiple boards, especially since it's after a PSU. I suppose moving forward I can run the printer off a surge protector (I was running straight from the outlet because I was testing power consumption a few months back and never switched it back).