...been watching this thread.

Has [bad] electricity been considered as a possible factor?

Dips in voltage that are not large enough to cause shutdown (or even dim your lights) can still cause undesirable system behaviors -- the resulting errors would be intermittent, inconsistent, and would likely affect all systems on the circuit (though possibly in different ways). Sound familiar?

Anyways, it's just a thought. I have seen it happen before, and hadn't seen it mentioned here.

Good luck!