This is good but without the extra words "extremely rare, potential harm.." this feels like it was a dangerous miss. I would worry about future such occurrences rather than just archiving it. Also I would definitely read more details. So perhaps this message works better in educating users
Last night, we logged out your Github account to fix a security flaw. Your account was not breached. You can read more details here [1].
[1] https://github.blog/2021-03-08-github-security-update-a-bug-...