Re: Wow. It's 2018 and "terminals" can still be hosed by sending files of control characters.
"Anti-aliasing, screen DPI scaling, kerning and graphics acceleration are a few extra complications to consider."
Fonts are just small vector drawings, there's nothing special about them in particular. The OS doesn't care whether they're a letter or an emoji. Now either there's an issue with the HTML/URL parser, the font mappings, the font drawing routines or the standard graphics subsystems used to render them. If it was the last 2 we'd have probably seen this bug long before now IMO.