It was suggested that it's a timing problem in omap initialization. If there's some kind of race condition in the code, then it can be VERY timing sensitive, so speeding up or slowing down a component, even by tenths of microseconds (as would be the case with temperature changes) can make the problem appear or go away. Race conditions are an easy mistake to make, and can be very hard to detect or identify. Once identified, they typically just require some extra protection in the software (usually some kind of synchronization object like a mutual exclusion lock (mutex)).