Alright so I suspect this might be a bug with the notification system.
Basically to repeat it you do the following:
1. Upload an unlisted post.
2. Someone else makes s public successor of that post.
3. You follow that post (the blue button that gives you notifs of comments)
4. Someone comments on your unlisted post.
5. You did not get notified of the comment on the unlisted post.

Anyways have a good day everyone.