LaTeX in WordPress: rendering glitches on old posts
I have a blog hosted on the free WordPress site with many LaTeX formulae, for which I used the $latex 2+3 = 5$ syntax. While recent posts are rendering correctly, for instance https://wildonblog.wordpress.com/2020/04/, all my older posts from before May 2019 now produce many rendering errors, for instance https://wildonblog.wordpress.com/2019/04/. The first error is for LaTeX formula
The HTML for these older posts rendered correctly at the time I wrote it, and I have checked that it is unchanged.
Has something changed in WordPress that might cause these LaTeX errors?