Boy that "st" ligature in the subheading font is eye-catching, to the point of distraction.

There's a lot of it in the article. Very distracting, I just didn't know what to call it (I searched for 'tail' before posting my own comment).

Agreed. I thought it was weird on the ct ligature on something like the second sub heading and the next one had a st ligature. I stopped reading the article and was just scanning for st ligatures in the text itself (there are none) and then realised the main font was a less legible serif font and the headings that were bigger and shorter were sans serif which makes the ct and st ligatures stand out even more.

I didn't read any more of the article after that, and the primary reason was just this weird font choice.

Indeed totally unbearable to even read the article

I stopped reading the article because of it.