OK, calling this one fixed. Motion sensor is linked to the micro on/off that controls the driveway lights. No idea when I did that, but it didn't happen by itself. Both components are likely 8 or more years old, so at some point I apparently got creative.
Proved it by physically disabling the motion sensor and everything began working correctly. Logs showed, prior, that the motion sensor would activate, and then when it turned off, the driveway lights would turn off. Symptoms stopped for the week that the motions sensor has been powered down and started back up as soon as it was powered up again.
Thanks for all the suggestions and help. I've spent more time on this system, especially in the ISY, in the last 2 weeks than I have in the last 3 years. Of course, that's now opened up some more questions/problem, which are for another post.