Notifications I am getting and their timing

Ok, I’m confused.

Originally I could understand the idea I post a message/thread and if someone replies I get a notification. And I did. In very short time, as well and notifications on this board (top right).

Now, I am getting notifications here and maybe 8 hours later getting the e-mails.

Really throws out my time line.

Also I am getting notifications on another thread and when I get to the bottom I see “get notification if someone mentions your name”.
Yeah, ok. But I don’t remember opting in to that thread, and I can’t (from quick scan) see my name.

The thread is “invoke every user defined time”

Just mentioning.