Hi @Adrien_Hombeck,
Thank you for your patience in awaiting a staff response. We’ve reviewed available diagnostics from the device and it appears that you’re encountering a known issue with BluOS grouped playback affecting the NAD CI580 in your setup in particular.
BlueSound is working to resolve the issue and we’re equipping them with all diagnostic and technical field data available to augment the investigation. With your permission, we’d like to request deeper diagnostics from your RoonServer to equip our teams.
Please see the main tracking thread here: NAD/Bluesound Grouped Zones out of sync, stopping playing, and/or skipping tracks [Investigating].
We’ll post updates on the main thread.