Reading other posts, tried answering questions previously asked.
I bought a brand new Roku Ultra 4670X 220.127.116.1107-46 and hooked to Visio TV E55U-D2 and experiencing audio drop outs of about 1-2 sec every 40-45 minutes. This happens on CBS All access and Curiosity Stream. It happens when HDR Subsampling is set to either 4.2.0 and 4.2.2. Audio leveling is NOT enabled. This happens on Klispche sound bar hooked to TV optical AND also happens on some headsets hooked to the RCA out of the TV. This Roku has also experienced random reboots.
This is NOT happening on a different Roku Ultra 4640X 18.104.22.16807-29 hooked to a Denon receiver in another room. That one works perfect.
My audio only dropped out for about 2 seconds but came back. I did find the resolution, i went back to the 4640 hardward build. it only happened on the 4660 hardward build. I returned the 4660 build to Best Buy and found a 4640 on ebay. But i'm still pissed off with Roku. Looking at the FireTV, had to side load Vudu so they aren't in good vibes with each other and all my movie collection is on Vudu. AppleTV doesn't support YouTube HD content. Just a bunch of bullcrap. Ultimately, Roku was still the best option.