They also ensure there's ALWAYS at least one notification when you sign in. Even if nothing of importance happened, they find _something_ to notify you about just so you can see the red notification count every time. I deactivated my account yesterday and look forward to a FB-free life.
Did you deactivate on purpose? Unless you still use Messenger or are considering changing your mind, you should delete your account instead. Deactivation just flips a bit; deletion actually removes your data.
Keeping in mind that this is Facebook we are talking about, I doubt the data is actually removed.