Well, I'm now having this issue on both my HR20s, with no issue on an H20. I verified the H20 when the HR20 lost signal. Also, I've seen one HR20 work, while the other didn't, and vice versa.
These three receivers worked without this problem two weeks + before the latest software update.
I AM 100% CONVINCED THIS IS A SOFTWARE PROBLEM. I've tried removing the B band converters too, with no change. If three receivers all work, and the problem creeps up on MPEG4 only channels then can go away in 10 seconds or 10 minutes sometimes, while all other receivers work fine, give me a break....It's bad software.