Possibly a bad clip on the 2nd stage ignitor connector, which is causing the connector to wiggle out during temperature changes like that and not allow it to hold in place.
This is not a total impossibility: at work, there was one projector in a classroom in particular that would lose power for no reason a few times a year. We found that the power connection wiggled itself slightly out after a long period of time and in-between seasons. It was still in the socket, but no connection was made. Our only explanation was that the expansion/contraction wiggled the connector loose.