I use a bunch of simple symbols in some of my posts (like ✦) and they get converted to unicode (%u2726) when I use the modify button at the bottom. The weird thing is, though, I've always used the button at the bottom, and it worked. I've only been dressing up the post in question since May, but May-Jan it worked great. I've seen the bboard spaz when you include an emoji it can't render/isn't prepared for, but that just hangs repeatedly, unlike this which is instantaneous. I feel like it's probably a question of Vekseid having changed the order of operations for whatever 'submit' does, or something simple like that.
What's the likelihood of getting the lower modify button fixed? It's easier to edit inline without switching to the full edit page and then submitting again to return to the original. It's easier to fix something based on someone else's post when you can scroll up and read the posts in order rather than the reverse order that shows beneath the editing box on the modify post page.