Hey all! I registered just to reply because I'm getting the picture in the corner of the screen, also.
Try this to see if you can replicate the problem at will: On TV2, tune to an HD channel, then hit or toggle the format button on the remote to Normal.
Then, on TV1, try changing the channel.
The picture shrinks every time to the upper left corner. Like as soon as I press "1" on the remote.
Short of a receiver reset, I can get the pic on TV1 back to normal by cycling the aspect ration to 4x3 then back to 16x9 in the HDSetup menu (6-4). (BTW, I'm using 1080i on that menu.)
My 722 just got the 610 software update yesterday, 8/5, and I just started seeing this problem last night, so it could be related.