Unable to add a user to a repo through 'Share' dialog if they have a common name

When I click 'share' at the top-right of my repo overview, i get a popup where i can search for the user i want to add.

After I type the full name, I get a list a 5 users with the same name, unfortunately the one I'm looking for is not in this top 5 list anymore (they were listed a few days ago), I'm guessing there are now more than 5 users with the same name.

Is the only way to actually add this person to know their actual username or email? Maybe admins should be able to scroll through all options when searching for a user to add.