I will be most interested in hearing how this plays out. Intermittent problems are always the hardest to diagnose, especially when the symptoms fluctuate. The only real rule I rely on is to go back to the last thing I did/repaired and take a very close look. Doesn't seem like this applies in your case.

A positive attitude may not solve all your problems, but it will annoy enough people to make it worth the effort. Herm Albright (1876 - 1944)