@sarahjamielewis Nothing is obviously wrong with it. This is just a guess, but it might be the capitalization on the unicode escapes? Mastodon capitalizes them. Here's a mastodon note that I keep around for regression testing
https://github.com/Letterbook/Letterbook/blob/main/Tests/Letterbook.IntegrationTests/Data/mastodon_post.json
@sarahjamielewis I put this together to help with interop testing. It's really useful to have access to mastodon's logs while you're trying to do this stuff
https://github.com/Letterbook/Sandcastles
If you have a fediverse account, you can quote this note from your own instance. Search https://hachyderm.io/users/jenniferplusplus/statuses/114644939393807869 on your instance and quote it. (Note that quoting is not supported in Mastodon.)