If you edit an user title and keep the same value for minimum posts but a different title you can't save it because it tells you that there can't be two user titles with the same minimum post value.
That's intended function, a user title cannot have the same number of posts as another.
But I edit the existing one. I don't create a new one. So after I save it there shouldn't be a second one with the same number of posts.
Now I see what the problem is.
Hi,
Thank you for your report. We have pushed this issue to our Github repository for further analysis where you can track our commits and progress with fixing this bug. Discussions regarding this bug may also take place there too.
Follow this link to visit the issue on Github:
https://github.com/mybb/mybb/issues/741
Thanks for contributing to MyBB!
Regards,
The MyBB Group