Issue: Mention glitch?

I was explaining to xxCyril about mentions and how we get notifications when we are mentioned but for some reason we both aren't getting a notification when we mention each other. I did receive notifications a few days ago about other people mentioning me and I haven't turned the option off, and neither has him.

This is him mentioning me link
And this is me mentioning him link

I also didn't receive a notification when someone else mentioned me a couple of days ago but I shrugged it off at the time.
Thanks in advance