Latest feedback I received via e-mail from X-10 tech support on the SC1200 and answering machines:
"I am afraid I need you to wait while I discuss further steps with the tech team and some of the developers. We are seeing a very high volume of support requests right now. Please rest assured that I am doing what I can to see the issue resolved, but it will take some time. As soon as I receive further information, I will let you know. Again, thank you for your patience."
This was after they had me provide the make/model of the answering machines I had tried and also had me try a test of answering the line with a phone after the answering machine had started recording. Hopefully the developers will identify a fix.
BTY: I tested my phone line and it is NOT a top/ring reversal problem unless it is the cord X-10 provided.