I was curious too (tho I don't really partake in the community) and this explains the situation:
https://lemmy.blahaj.zone/post/20976989
Prob a highlight of how Lemmy needs to solve community migration cross-instsnce properly as well as how community moderation vs. instance moderation will always be a problem in reddit-like fediverse implementations.
Not everyone at a company can be managed by group policy or in-tune or whatever. Like if they aren't using windows. You can run into the same situation on macOS or Linux depending on if you have the old and/or new clients installed at the same time.