Discourse has what it calls “trust levels” where basically members who have been around longer and have done things that make them more “trusted” have permissions to do things that regular members can’t do. We don’t use trust levels and had attempted to pretty much disable them, but our initial settings for that were not correct and some people ended up being promoted to higher trust levels where they could edit titles and could do a few other things that we intended to be done only by moderators.
We have since fixed the trust level settings.