User Follower (bell symbol) general question

Hello, can you explain more about what happens when a user Follows another user?

From what I read, it means that if User A follows User B then User A will get email notification whenever User B makes a new comment.

But, does that follow only exist in the post/page where the initial follow occurred? The system works correctly on Post 1 (User A is emailed when User B makes a new comment). However, I tried testing when User B makes a comment on a different post (Post 2), and there was no email notification sent to User A. So does this mean the follow only "lives" in whatever post it occurred?

If so, then the follow (bell) symbol is showing incorrectly. On Post 2, the bell symbol is still highlighted to show that User A is following User B. And when you hover over the bell it say to click to stop following User B.

Thanks