I see some good news in the latest release notes: Roon 1.4 (Build 298) Is Live!:
- Zone Grouping stability and syncing fixes
Sounds like the devs have a fix for this problem in the latest release. I just tried a grouping setup which had been flaky in the previous build a few times in the new Build 298, and so far I haven’t been able to get grouped Roon play to fail the way it had been. I’ll sure chime in if I see a suspicious failure in the future, but I’m initially quite hopeful that this bug has been squashed.