In the community configure page (under Members), if you search the display name of a user that is in the group (or begin to search it), they will not appear. You must type their EXACT username to find them.
As you can see in the video, I search my own username, and I appear. I then search my display name, with no results.
The member search feature should function like the Friends CONNECTIONS search feature, where users are displayed if you type their display name/username or similar. This would make it a LOT easier to find a certain member.
(this topic was moved from Bug Reports)