Don't know about the changes.However, being on 101 can mean a couple of things. If the guide is not downloading fully, at some point the receiver gets confused and it will go to 101.
For some reason your receiver may be resetting while you are gone (or you have it set that way), or does it when the guide is not fully downloaded, or a sign the hard drive is having problems. When it resets, landing on 101 could indicate you left it on an HD RSN, and when the receiver reset, it could not go to the HD RSN (off air) so went to 101, or, you were on a channel not in the custom guide you are using. Or if you watch a channel like TVJapan for the free news and left it there. Or, just in general it was left on a blocked out channel, for instance sometimes ESPN blocks a ballgame, if it was left on ESPN it will/can kick to 101.