Just in case you receive no other confirming replies, I followed your steps exactly, but got no 771's on an HR20-700 running NR software.
I first noticed this problem a few weeks back in that I cannot watch any of the HD channels from Sat 103b on Tuner 2 if I am recording an HD channel from Sat103b on Tuner 1, and vice verse.dbsjasper said:Glad I'm not alone. I have an HR21-100 as well with software rev 0x255.