I'm glad to hear that I'm not the only one seeing this same fascinating problem.
At least I don't have to wonder if my CM15A got damaged, or corrupted, or something. It isn't convenient for me to leave it connected to my PC all the time, as the location where it works best (due to distances to the receivers down in the barn more than 250 feet away) is not near my desktop computer. I've been running it as a standalone unit for years, only connecting to the PC when necessary for updating the program. And it worked great until the DST date change last year.
I tend to be sympathetic with programmers, as I was one in a previous life. So I understand it can take some time to fix a bug and allocate appropriate time for testing to be sure you didn't create new ones. But I have to believe the support people have now had
plenty of time to get this fixed. Yet I have not seen a single software update since the DST change last fall. Very disappointing. Perhaps it's not fixable through an update to the ActivehomePro software, and requires a firmware (hardware) upgrade in the CM15A. I sure wish somebody from X10 would address this issue and let us know.
Jeff