Hello @Wolfgang_Halter,
We’re hopeful that NAD is able to provide more insight into what you’re experiencing here. And we’re very pleased to see that you’ve gotten some great assistance here from some of Community’s most knowledgeable contributors!
When customers have issues with grouped Zones we generally recommend rebuilding the grouped Zone in increments to detect the cause trigger. Play to just one Zone for a bit, then add another, play for a while, then add another. This helps to reveal the inflection point for the failure.
I wasn’t sure if your comments in this thread mentioned it but, we also wanted to let you know that there’s a new Linux specific release that you may want to explore, you can find more info on the latest build here: