u/FoxhoundFPS, This is a bug when in CaC when you queue up for Quick Play. When queueing, you are unable to add items to or remove from a class. It shows X/0 items when it should be X/10. This only happens during matchmaking for Quick Play. Other playlists it is fine.
This was shared with us today. I've sent it to the team and will add your thread along with that report. Thank you!