As Mr Volp has been better for this system than anyone I have heard of, listen to him and don't give up on x10 without a fight.
I have been dealing with some "X10 Madness" myself lately. Over the last week several lights controlled by X10 were on when they shouldn't have been. I plugged in my XTBM-Pro to log X10 traffic, and it didn't record any X10 commands corresponding to the lights being on. This has effected both X10 floodlights and Leviton X10 compatible wall switches.
Then this morning the garage exhaust fan was on. Our Ocelot program turns that on to pull in cooler morning air if the garage had been very warm the prior day. But yesterday was not warm, so the fan should not have been on. I sent the X10 OFF command to turn it off, but surprisingly, a couple seconds later it turned back on. I sent the X10 OFF command multiple times, and each time the fan turned off and back on. I checked the XTBM-Pro log, and each time it recorded the OFF command, followed by an ON command. Since it always responded to OFF commands before, I don't have a clue where that is coming from.
While not entirely X10, I've also been dealing with an irrigation issue that started about a month ago. I noticed one of our irrigation zones had not turned off. I've had valves stick in the past, but it was not that. We have used a WGL Rain8 for almost 2 decades, and except for having to replace several triacs over the years, it has worked well. It goes through a predetermined cycle initiated by an X10 command. It apparently had stuck at the transition between zones 2 and 3. I swapped in a spare Rain8, and the problem seemed to go away. But a couple of weeks later zone 2 was stuck on again. Cycling power cleared it. Maybe a week after that zone 3 stuck on. I swapped in another spare and even replaced the TW523 that receives the X10 commands. But this morning zone 2 was stuck on again. It is like somehow the timers in all three units are malfunctioning. The XTBM-Pro only logged the X10 command that initiates the sequence.
X10 signal and noise problems are easy, but these have me puzzled.
Jeff