Dolby Atmos not working anymore after Lego Update

Hello together,

I have enabled “Dolby Atmos for Home Theater” in Windows. Dolby app, other games like Metro Exodus, videos, Netflix is working with Atmos.

But since the newest Forza Horizon 4 update I only get 7.1 sound. Anyone else having this issue?
By the way I noticed that in several patches. Every patch is a hit or miss with Atmos sound.

Can anyone help?

Regards, Oliver