Yesterday, a contributor (questioner) on a site was suspended for 365 days. That very same person, with a thinly veiled avatar change, returns today as if nothing has happened! It would appear that it's OK for this to happen. What's going on here?
It would appear that it's OK for this to happen.
No, it's certainly not OK. It's just that the ♦ moderators didn't notice the new account yet – they're not online 24/7. You can flag one of the posts for moderator attention and explain that's a suspended user breaking the rules.
I did that just before writing this answer, and the new account has now been destroyed.