The problems I saw earlier with raw markdown coming through appear to be affecting meta as well. I’m following @feature@meta.discourse.org and some hours ago, this post was created that was federated from that Actor:
This showed up for me in Mastodon glitch like this:
In Elk, it looks like this; a little better:
I just started following @feature@meta.discourse.org in my pure Mastodon account now to test this, but of course that’s too late to see this particular post there. 
So the embedded markdown I saw earlier from my own install wasn’t a bad database, or if it was, it was a database problem shared with meta and thus probably not associated with my testing.