The PM system, the new "Add Friend" system, and the @handle suggestion system in chat all have a bug that causes users sometimes to not show up in the list even if you type their exact handle into the search box. For example, one of the helpdeskers - @Fyre - doesn't show up in the list of you type @Fyre in chat or Fyre into the search box. He does show up if you type his moniker FyreMaster though