There is the font `dustismo_bold.ttf' (from openSuSE's `free-ttf-font'
package). fc-scan gives the following output:
Pattern has 19 elts (size 32)
style: " Bold"(s)
fullname: "Dustismo Bold"(s)
I think that fontconfig should remove the superfluous space so that
the style is `Bold'.
Well, I think ideally it should be fixed/correct in the font though, we can have a workaround for that.
Fixed in git master.