I have a pretty fresh Debian 11 installation, running in a VirtualBox VM on Windows 10. The fonts in question look as if each glyph has many missing parts / as if the visible parts, such as they are, are correct.
I must have forgotten to install or configure something, I think.
Visual Studio Code has a mangled title bar, but all text inside the application renders correctly:
MonoDevelop is completely fubar:
Jetbrains Rider the same:
Attempts to diagnose the problem:
- I tried all the pre-installed GUI applications and none of those are affected,
- all three applications display fine on a Debian 10 similarly set up and running in the same VBox,
- only Rider produces any errors and it produces the same ones (line-identical) on Debian 10, where "it just works"(TM), so those errors are unrelated.
I am a bit lost.
... Probably unrelated: I have the same issue on Android 11 in BlueStacks 10 with Firefox. I am adding this in case the issue is not of the client OS but of the server OS or virtualisation software.