Ask HN: Looking for a tech talk on bold having no effect for certain fonts

Does anyone remember a talk that was submitted to HN in the past few months, it may have been in the comments.

It was about a user submitted bug where bolding text for a certain font had not effect.

The talker goes into the unexpected complexity of fonts, font packs, etc. and why bold might not work for certain fonts.

I've searched high and low but cannot find a link to the talk.