The motion lights out side could be be X10 ones? Its a chance that they are sending the same code as some of the indoor lights....or maybe something is messing with the signal and it is causing false signals from the motion lights...
Still a stomper but something else to check out!!!!!!!!
Good idea.
Have you noticed any correlation to the lights outside? Dusk/Dawn?
Lights might look like
this with settings like
this. <--- Click the "this" links.
If so, let us know what those settings are. One of these type lights could be effecting up to 8 or 9 sequential UCs on it's HC. Still not sure why it would take 6 months for it to happen, however.
If you're really bored, you might repeat the "All Lights On"/"All Units Off" test with your controller plugged into a few different outlets. I'm not really expecting any different results but it's possible a signal didn't reach a house next door. It's a "grasping at straws" test that most likely won't give any different results but we're running out of new things to try.
Another thing that has a small chance of helping would be for you to rotate the HC & UCs at least one or two full turns both ways.
Return to the same codes. It's rare but I believe there have been a few cases of oxidation on the contacts that have influenced settings.
As mostly a curiosity question, how old is the house?
I'm beginning to think I should document my house for a some future owner for when I move on to the "great automated house in the sky". Of course I could just come back and use X10 to help me haunt the house.