Ok, next idea- check your config.toml file, is this line in there?
https://github.com/gcushen/hugo-academic/blob/master/exampleSite/config/_default/config.toml#L62
Reason: late last year, Hugo switched the default markdown renderer from BlackFriday to goldmark. See https://gohugo.io/news/0.60.0-relnotes/. Goldmark by default calls all raw HTML code unsafe, so you need to configure goldmark to allow raw HTML. I'm not certain this is your issue, but this is what I would check next.
