My brother has a Sony KDF-E50A10 Rear projection LCD and uses a Motorola 6412 with component cables. He's had this setup for about a month now, and this issue has just come up today after a power cycle on the 6412. Basically what has happened is he has lost his "Normal" in the wide mode menu, so any 4:3 channel he watches is automatically set to "Full", and he can change it to anything but Normal. All his other video sources seem to behave normally.
He talked with a Sony rep, and after some troubleshooting he decided it must be a problem with the comcast box, because other components, like the DVD player, don't have this problem.
What I tried was unplugging the 6412, swapping the cables to a different component input, and tried the HD zoom button on the Comcast remote. Nothing worked. For now I've told him to plan on swapping out the 6412 for a different one on monday, but I thought I'd check in with the experts here and see if anyone had an idea what the problem is, and hopefully a fix.