Hi Dan,
Thanks for reaching out! My name is Erin, and I'm on the Help Team here at Moz. As far as I know there's nothing wrong with the mentions feature, but we need more information to be able to look into this for you.
If you feel like you've found a bug, the best thing to do is to email us directly at help@moz.com. Q&A is a great place to ask the community for SEO advice, or to ask about functionalities of the tool. But if you feel like you've found a bug, the best thing to do is email us so we can troubleshoot and investigate. In order to really dig in to issues like this, we need the following information:
- The affected campaign
- The specific issue your seeing (in this case we'd need to know the query you're trying to add so we can test it out)
- Screenshots of the error message you're seeing.
I hope this helps, and we look forward to seeing your email!
Cheers,
Erin