Network icon in GNOME title bar flickers sporadically with network bridge

After creating a network bridge (for QEMU), the network connection on the top right flickers, which means it sporadically disappears and then appears again after a short while.
The time between the icon disappearing ranges between 5 minutes and 45 minutes, most of the time it's around 10 minutes.
The time between the icon re-appearing ranges between 1 seconds and 2 minutes, most of the time it's gone for around 3 seconds.
There's no apparent correlation to any user behaviour, it happens independent of the network being idle or under load.

The physical network traffic is not affected, i.e. the network connection still works while the icon is gone.

The network bridge was created with 'nmcli' according to this guide and works flawlessly: https://www.answertopia.com/ubuntu/creating-an-ubuntu-kvm-networked-bridge-interface/

Description: Ubuntu 22.04 LTS
Release: 22.04

package and configuration details: see attachment