Hmmmm. Thanks for running those tests.
I don't currently have any way to test for noise. I really think it's noise related OR something that I just thought of as I was trying to figure out why only these two Socket Rockets have this issue. In addition to the very real possibility of it being a noise problem, it may be some sort of wiring issue on this particular circuit. I'll have to do some logical trouble shooting to narrow this down but I have a Home Theater system that I
think is on the same circuit as the offending outside lights/socket rockets (part of what I need to confirm). It includes all the equipment shown in the 'Home Theater' room on this diagram:
http://farm5.static.flickr.com/4030/4343410503_505e5d0313_o.jpg All electrical connections for the system (except the Sub woofer) are made through the APC J15BLK Conditioner/UPS -- which is connected through an ACT AF120 Plugin Filter Module to help with X10 transmission issues.
Whenever a significant power fluctuation of any kind occurs, the APC J15BLK Conditioner/UPS will take over and supply 'clean' power to the A/V system. When it does this, it beeps and I can hear the APC's fan fire up, the front panel lights come on etc. Anyway, it's done this fairly often (nothing to do with adding X10 to the house). Further, it has done it sometimes for a few seconds when I turn on the garage or deck lights -- manually or via X10). Sometimes it does it for no apparent reason and I have often thought I need to have an electrician come in and look over the whole house to see what's up electrically. This instability may indicate some issue with the wiring and therefore the root of the X10 issue we're discussing here. It may have nothing to do with my issue but I'm not sure. It may also be that the APC unit is being overprotective too.
I may also have to buy a noise meter too. Until then, I'll have to attack this logically and determine what's on the offending circuit.
Thanks for the feedback and ideas. I'll keep working at it.