I’ve condensed the shell extension “system-monitor” into a minimal example that exhibits the problem: GitHub - rschupp/sm-minimal: Minimal test for https://github.com/paradoxxxzero/gnome-shell-system-monitor-applet
The extension shows (in the panel) 3 St.Labels “weird”, N, “°C” where N increases once per second from 1 to 99 in steps of 7, then wraps back to 1. But the most significant digit of N seems stuck and you can see small artifacts between the two digits as if only parts of the label text get correctly updated. When I move the cursor into the extension area the correct number is displayed, but deteriorates afterward. See the video https://github.com/rschupp/sm-minimal/blob/main/panel.mp4?raw=true
What could cause this effect?
PS: I’m running gnome-shell 40.2 on Wayland with mutter 40.2 and gjs 1.68.1