V 0.92.6 Enables "Dry Run" randomly during printing (no replies)

I can check the setting in the LCD "debug" menu. Dry Run off.

Then I start a multiple hour print - say, 3 hrs. Halfway through, it stops extruding. The first time this happened I thought it was a jam, as nothing I could do would make it turn the extruder. Then I found I could push the filament through with my fingers, and realized that wasn't the problem. After some research I checked "Dry Run" and it was "on".

The next time I saw it stop extruding, I went to debug and sure enough, it was on; I turned it off and it started extruding again immediately.

I can print small stuff no problem - 45 minutes, whatever. It's happened a few times. But every time I try to do something that's a few hours, this happens, and I get half an item. If I'm watching it, I can turn dry run back off and it goes fine. If I'm not I find half an object printed.

Any thoughts?

It's a custom build CoreXY, using a Mega with a RAMPS 1.4, Repetier 0.92.6 (Though I downloaded the 0.92.7 firmware, it still declares 0.92.6 in the Repetier.h file), simplify3d.

Thanks in advance!