Some characters "missing" in some fonts

I'm having a weird issue where some fonts don't display some characters in some contexts. In [this example](https://imgur.com/a/5woMYf6), I have `show-paren-mode` enabled, and highlighted parentheses are not displaying. In fact, this *only* affects the font Iosevka as far as I can tell. Does anyone have any idea what's going on?

Something somewhere is changing which glyph is being displayed. If possible, when the glyph is being displayed incorrectly, move the cursor over it and do `M-x describe-char` and find out what is actually being displayed. That might then give some clue as to what is needed. My suspicion is you've got something installed which is replacing characters as some sort of current line "highlighting" thing. Or I suppose it could just be the theme playing with fonts for specific faces.

Thanks for the tip. I think something was wrong with my fontconfig data; I deleted the fontconfig stuff under my home folder and everything worked again.