"Host Application Not Running" - but it is running...

I have GPU passthrough running with Looking Glass on my Debian 13 host. It works well in principle, except for an error message that appears shortly after starting the Windows guest.

The Looking Glass client on the Linux host seems to think that the Looking Glass host application is not running.

However, as you can see in the bottom right corner, it is running. In addition, Looking Glass is working and using the second GPU, including hardware acceleration.

My setup:

Host GPU (Debian 13) - Nvidia Quadro RTX 4000

Guest GPU (Win 11) - Nvidia Quadro P4000

Looking Glass version: B7 (both host & guest)

qemu: 10.0.3 (Debian 1:10.0.3+ds-0+deb13u1)

Host OS: Debian 13

Guest OS: Windows 11

Any ideas?
Best regards
Ralf