Thanks Daniel!
Here is another report of this issue, in case the devs need more info, and to help prioritize: Issue with Roon ARC playback interruption on Xperia 1 V (ref#1JYUUD) – this customer said the issue went away after a reinstall, but I suspect it has recurred since then. I followed their steps, and I also saw the issue go away, but then it came back a few days later. Same thing with just restarting my phone.
I hope this also gives a better sense of priority.