@mentions sending out 2 email notifications

When I make a @mention on a page or comment it is sending two identical email notifications out to the user.

They are both at the same time and about the same @mention. I can see the two emails in the view mail queue as well.

And this isnt from watching the page (I get a separate email for that, if I am watching the page as well).

So far I have not found anything that stops the two emails being sent out.

Do you know why it might be doing this?

Thanks,
Daniel