FYI your Facebook profile and Messenger account seem to be decoupled now. I deleted my profile but still have a Messenger identity that people can message.
Unfortunately, I'm not sure I deleted it. You may be right.
My main goal was to harm Facebook's ad business, so I still accomplished that. As far as privacy, I've mostly given up on escaping from Facebook's databases.
The behavior you are describing reminds me of the behavior that happens after deactivating your account, not deleting it.
I deleted my facebook last year so maybe things have changed.