I've had 3 fails in the past 3-4 weeks. There have also been several successful cooks. This seems to happen on cooks > 6hrs.
I will set the temp to 131. Instant read confirms a good temp.
Sometime over night, the water reached 203o.
Reset it and it seemed fine. Two nights ago, when I got up in the morning, the temp was down to 120o.
Just now, after 5+ hours of a good temp, it shot up to 151.
To be clear, the display ALWAYS reads 131 no matter what the true temp is.
I get the accurate temp from my instant read.
Doesn't happen all the time. Can't predict it. But sure can't trust it.