Yeah, why would that
</div> switch fix things? If anything it’d only affect coding afterwards.
Anyway, I presume the problem might be due to a JS mistake or missing JS. If you look at the source code of the Support Lines - Butter Comics 2020 post you can see coding for all the various notifications. I’m not sure if that should all be there. Either way, it’s not displaying in the browser due to
display: none or JS functionality or whatever, however Discourse nonetheless picks it up due to not using the same CSS or JS or whatever it be to display things.
My guess then is that you’ve either changed or removed some JS which is resulting in all those lines of code appearing in the post’s rendered source code, or there’s a bug in the theme. Having taken a look at the source code of a demo post of the Melaka theme (which I see you’re using) I don’t see the errant code. I presume then that you’ve done something that would otherwise be stopping that code from being “injected” into the post (and, in fact, into every single page/post of your site I see).