Problems with a stable HDMI connection, Roon OS build 260 early access installed on NUC12

Hi, Roon.
My NUC (ROCK) is connected to a Marantz SR6008 with HDMI. Early Access build 260 update is installed on the server. This works fine, no dropouts or problems, great sound.
The only problem I have is that when the amplifier has been switched off for some time, e.g. during the night (The NUC is 24/7) I lose the connection to the Marantz. The only way to restore it is to stop the NUC (restart does not work). This happens maby one out of five times.