Hi Walter,
Yes, this is on a shared folder.
I am manually putting in the email of the person who I want to tag.
I'm putting it in manually in hopes that dropbox will populate the rest of the name.
The names of everyone else on the folder, when mentioned, populates except for 1 person.
It kind of messes up workflow when having to remember their email or go back to an email and have to copy and paste from one tab to another.
I will try clearing my chache and see if that works.