So, multiple staff members have been encountering an odd error since yesterday. It's difficult to fully test though, because when it happens, the site entirely stops loading for them -- sometimes for hours.
Basically, when they try to edit a post that is not their own (witnessed with both the rich-text and the bbcode editor), they get this error:
And then the site seems to lock them out. It fails to load entirely. I logged into one of the admin's accounts and was able to access the site. But when I duplicated the error, I was then locked out entirely on my desktop. I tried different browsers, and also cleared my cookies/cache/everything, but it still fails to load. However, I could load the site on my tablet just fine.
The time they get locked out for seems to vary. So far, it's been anything from 20 minutes to several hours before they can get on again.
I haven't done any updates or installed new mods for the board recently, and the threads that we're getting these errors on so far were last successfully updated on Friday. Not sure if it's related, but the people who experienced the error first were just promoted from moderator to administrator yesterday.