What is this?

Notice the players who have no avatars or checkboxes. They can be selected by clicking on the name text, at which point they will turn white. They can then be de-selected by clicking a second time, causing the name to change back to black. Please note that some of the players that appear as plain text actually have custom avatars.
Are these players using Impulse Reactor and not Ready to Play? Could that be why? Have you guys added preliminary support for that sort of matchmaking? Or is it just a bug?