I also have an Onkyo 885 . When I am playing audio (SACD or CD) on my PS3 and shut off my tv (older JVC HD-ILA), the audio output on the prepro cuts out for about 3-4 seconds, then returns. This happen at the point the TV fully powers down (cooling fans shuts off), not when I initiate the power down. I do not get a track restart though, as the PS3 ignores the process.

So it sounds like it depends on the source, and the TV as well.

BTW, you can not get the 5.1 mix off of an SACD/PS3 via analog or optical, only stereo. If there is no stereo mix, you get nothing. There was a firmware that gave you a DTS conversion of the 5.1 DSD briefly, but it is long since superceded.