Editing a post on Iceshrimp crashes the app

[Tournesol-me]

Describe the bug
Trying to modify a post on an iceshrimp instance crashes Megalodon and Moshidon but not Mastodon. It might be related to
It apparently crashes specifically with content-type set to text/x.misskeymarkdown.
To reproduce

Steps to reproduce the behavior:

1. Post a simple message like "hi"
2. Edit the post
3. App crashes instantly

Does this happen in the official app?

Does this issue also occur with the respective upstream release?
No

Version

Megalodon version: v2.1.6+fork.110