My BP50 Preamp looses sound often, especially when shifting streaming service on TV

My BP50 Preamp (Tag in this system is missing this label) loses sound more often than not.

This is a weird periodic flaw in the DAC.

My connections are
From TV to BP50 via HDMI ARC I only use TV as source.
Into BP50 via HDMI ARC
Aout from either RCA to external speakers
Via Blutooth APTX AD which works flawless (this connection never loses sound when connected.

Apparantly the ARC sound is dependent on the input the TV gives it. On the TV I switch apps/streaming services often.
Usually no problems with streaming from different sources like (Spotify, Netflix, Viaplay etc.)
But when streaming from Google TV shop. The sound stop the stream altogether or I lose sound in RCA output/BT. The sound also disappears from other streaming services more and more often.

To try and fix/troubleshoot the issue. I have switched input to line, and after 20 sec. the TV picks up the change and writes TV speakers active on the screen and sound is active from TV speakers.
Clicking back to ARC input, sometimes sound will start after a couple of seconds. Or it will be muted, whereas I turn op and down the vol. This has worked many times.
But now after one month of use. The problem seems to be getting worse. And I am now losing patience with work-aorunds. I need sound that just works.

I see no apparant pattern in this. What can be done. I am in the proces of returning the BP50 to Amazon. But I really like the sound and general design. So hate to do this. But the sound dropping out is driving us crazy…

Please help