I was wrong.
I was on the right track, though. Something WAS confusing the timing button/sensor/thingie, but it wasn't dust, condensation, or even nicotine residue.
In fact, it was the lack of condensation that led me to the culprit.
THERE WAS SOMETHING LIVING IN THERE, AND IT WAS THIRSTY.
I have no idea if the suspect had wings, fur, or a tail, but it was served an eviction notice via my hammer. (Seriously, I heard that little bastid running for it's life!)
I hope it died of lead poisoning.
Serenity is beepless sleep. And like an idiot, I stayed up all night. Sheesh.
Ain't that just like me though? *grin*