The @ mentions on the mobile app show the username instead of the nickname field when you autofill them. The @ mentions on the web platform show the nickname. See the screenshot below. The behavior should be the same on both platforms. We use numbers for the username and the @mentions in the mobile app don't make sense. Here is a screenshot. https://www.dropbox.com/s/fnhizxtt25logna/Mentions%20on%20web%20vs%20mobile.png?dl=0 Thank you!