Thanks for getting back to me @Christoph_Schmid and my apologies for the slow response.
Moving forward, I would like to have our techs take a closer look into this behavior you are experiencing with the Tana SL-1, so I have went ahead and enabled diagnostics on your account. What this action will do is generate a report containing a set of your logs that will be automatically uploaded to our servers when your Roon core comes online next.
Furthermore, I would like to have a complete understanding of your current setup for my report to our tech team. With this in mind may I very kindly ask you to provide brief but accurate description of your current setup using this link as a guide.
Lastly, I want to be up front there may be a chance that we will not be able to do anything until we try to get one of these units (i.e the TANA SL-1) in house to test with. Obviously this depends on if there is anything noteworthy in the logs, etc.
-Eric