Comment # 66 on bug 904015 from Petr Gajdos

(In reply to Vadim Krevs from comment #63)
> Created attachment 713185 [details]
> 3. Fonts in a default Leap 42.2 install with your fonts.conf (option 1 from
> comment 56)

Let us please stick only on this case. I assume you have not run KDE's font
dialog for that user, please double check that ~/.config/fontconfig/fonts.conf
for that user is still the same as you cat in the screen shot.

I think you already know, please do not test now on KDE font dialog at all, the
result would be misleading.

What says 

$ fc-match -v sans:size=7 | grep 'family\|hint\|alias'
$ fc-match -v sans:size=8 | grep 'family\|hint\|alias'
$ fc-match -v sans:size=9 | grep 'family\|hint\|alias'

on that system for _this_ user?