I was having issues with my older Sony BDP-S670 constantly dropping audio on netflix yesterday, so decided to disconnect it and put the Premiere+ back on the 1080p setup, and that worked correctly during the time I used it. Which brings me to the purpose of this post. It seems like the AV delay I experience with the Premiere+ seems to only happen more with stereo sources, or more of the free services such as TWIT, Pandora (music), Plex (both video, and music). I haven't tried extensively with YouTube, but it seems like if I have issues with particular content in one service, the same problem shows up with the content regardless of the service.
After taking some time with a cool head to really spend some time with the ROKU Premiere+ and seeing what works reliably, and what has issues, it seems like all the standard services such as Netflix, amazon, VUDU work with very little to no trouble. Things like the Boomerang service, that's not standard with every unit, but someone can add and pay for, also seems to work. Smithsonian Earth is also a low cost service I pay for, that I don't remember having issues with. So, with further testing, it seems like the AV delay / over driven audio only really affect me on music, or podcast / YouTube style video / audio.
The last thing I wanted to mention, is I took my complete setup (since it's stereo on that setup) to all devices set to PCM stereo output and doesn't fix the random issues. When I had the ultra, this would usually fix it. With the Premiere+ when I first got it, it was still on 7.5.5, I think or it could have been 5.1 and it never had the random issues. The issues showed up on the Premiere+ within the last few updates. With this said, changing to a different device for the standard service isn't an issue, even accessing certain stuff through YouTube instead of the ROKU channel isn't an issue, changing from the Plex client to DLNA isn't an issue. Boomerang, and Smithsonian earth work with chrome cast, or Apple TV. I still have my streaming stick that works without issues for the time being. In the end, it would be nice not to have this big platform gap, and whatever device someone chooses would have all the same content available, it would make situations like these much easier to deal with quicker.