Locale is also set to en_US.UTF-8 and has never changed
I can change the font to ttf-hack and it works, but then when I switch back to Ubuntu Mono I get the missing symbols again. So it seems like an issue with the Ubuntu Mono font specifically. I'm not sure what exactly about the KDE 6 upgrade would've broken it.
I've been using Powerline on Arch with Ubuntu Mono for years and it's had no issues.
For some reason after the recent KDE 6 upgrade, the Ubuntu Mono font seems to no longer work, the symbols are missing so it looks like artifacts.
I have both the powerline and powerline-fonts-git packages installed as per the Arch Wiki: https://wiki.archlinux.org/title/Powerline
Locale is also set to en_US.UTF-8 and has never changed
I can change the font to ttf-hack and it works, but then when I switch back to Ubuntu Mono I get the missing symbols again. So it seems like an issue with the Ubuntu Mono font specifically. I'm not sure what exactly about the KDE 6 upgrade would've broken it.