https://bugs.kde.org/show_bug.cgi?id=404652 is related? Probably... because another thing I noticed recently is some file extensions do not appear with an icon in Dolphin, just blank.
https://bugs.kde.org/show_bug.cgi?id=404652 is related?
https://bugs.kde.org/show_bug.cgi?id=404652
is related?
I noticed it too :(