So I think it has to do with Single->Dual and Dual->Single when starting and stopping the SA. I did a test this morning where I started 2 recordings. I think manually set the reciever into Dual mode. I went into the bedroom and had no issues getting a video to play. I went back and changed it to Single with the recordings still going. At this point, interesting note. When in single with 1 or2 recordings you get just the one red light. When I switched to Dual I got the 2 red lights, one for each TV. When I put it back to Single, it went back to one red light. So now I am in Single, I go back to the bedroom and again can watch video. So I stop using the Sling and go back to the receiver. It says its in Single but showing 2 red lights. I go to the channel with the recording on TV1 and hit stop. It asks me to stop the recording, which I do. The guide shows it not recording, BUT the DVR menu still shows it as recording. Go the the channel with the recording on TV2, hit stop, nothing. Can't manually stop these two recordings. I have to reboot the box to fix the issue. So my workaround right now, and its not a huge deal since I am the primary Tv watcher, is to put the receiver in Dual mode when not in use so I can use Sling and not worry about it.
Edit:
Did another test right before work. Set 2 recordings (Show1 on TV1, Show2 on TV2), manually set Dual mode. Went to the PC, tried to watch Show2 from beginning for DVR. Kept getting "The Sling Adapter is starting up". Tried Show1 from DVR, started fine. Back to Show2, "starting up". So went back to the receiver, put it back into Single. Saw that Show2 now had a 2 minute recording along with the ongoing recording. Show1 was fine. Was able to stop both recordings.
So there are some bugs, I will concede that new Tech has its bugs. I get some split recordings. But there is definitely a flaw in how the SA handles the switching from Single->Dual with recordings are being performed. I don't think its switching back from Dual to Single in the right way and I also think switching from Single->Dual is messing with recording and watching from the DVR.