I have raised this before and been told it was solved in version 1.2 of Flarum. However I don't believe it is.
The problem: There are 3 editing permissions for users to edit their posts:
10m - This is almost worse than useless, you might as well not allow edits....why not 1 day, or something a little useful. Often people only see an error when someone replies, or needs to correct an omission that's being pointed out to them
Until next post - What does this even mean, the users next post anywhere, next post in the thread, anyones next post in the thread. If it's the latter, that could (on a busy forum) effectively be an edit time of 30s!
Unlimited - Unless it's a closed forum, this is of absolutely no use......the reasons should be obvious, but here's two. Spammers often use the tactic of registering, making a post, then if they can go back and edit it a few months later (remember flarum doesn't show or flag an edit!)..they put in some spam links, or whatever..bingo, pretty much undetectable unless you're manually searching.
An abusive user goes back and edits an old post to add abuse, or many old posts...you have no way of knowing unless it's reported or someone scans the forum. ..or adds porn images etc..
So in my opinion as user options, on a busy public forum, until next post and unlimited don't make any sense at all. If using the shadow ban function, it makes it a bit useless as well.
Please can you change the 10m to a time configurable option in hours, so I can choose 6 hours, 24 hours 48 hours 100 hours etc..