I set my parents up with a Sound Touch 300 system on their Samsung 8000-series 4K TV. I have a STB (Tivo) going into the Bose HDMI in, and the output of the Bose going to the Samsung's HDMI ARC input (HDMI 2). I also have a BD player on the TV on HDMI 1. The Samsung AnyNet. The audio return channel works fine for both sources, and the Bose ALWAYS turns off consistently when the TV is shut off. However, it DOES NOT consistently turn on with the TV, leaving a INPUT MISSING error, which my elderly parents are having a real issue with. All they have to do is turn on the sound bar with it's remote, but I'm trying to make this simple for them. One remote to turn on the TV and the Bose should come on automatically like it is supposed to. But this isn't happening. Maybe 25% of the time (usually after a long power off) it won't come on with the TV. Auto Off is disabled on the Bose. I'm not sure if this is a Bose or Samsung issue but was wondering if anyone has experianced any issues like this with a Bose or other external sound bar.
It's likely a compatibility issue. Have you tried connecting everything to the television and then only using ARC? Set ups get a little convoluted whenever there are two different devices with input sources on both.
My next attempt will be to put the cable box (which is always on) on HDMI3 and the BD player on HDMI1 and have the Bose speaker on HDMI2 working as ARC only. However, I'm not convinced that will do it, because the ARC always works 100% fine on either source, it's just the automatic power-on feature that is problematic