There was a test a bit back and mbin -> mbin ampersands work: https://kbin.run/m/Test@gehirneimer.de/t/181055/Does-Mbin-support-and-in-title it’s just ones that come in from lemmy that end up like that. I’d have to look up the rules of markdown parsing but I imagine lemmy emits the character as escaped, but not sure that’s expected for markdown vs html. Still might be worth double checking, the markdown library mbin uses might have differences, it definitely doesn’t support superscript which we’ve discussed but the extension to do so hasn’t been updated in years and doesn’t work with the latest versions of things we’re using, for example

edit: It’s always possible I’m missing something like maybe it’s only link/images posts or something else, so will try to double check