While attempting to switch drop decks from deck 1 to deck 2, all of the mechs in deck 1 became listed as Ingame and all of the mechs unavailable for play. Exiting MWO and logging in again does not release the mechs for use again. All the mechs in drop deck 1 are locked as being Ingame.
Also note that the mechs in question were not in any prior match at the time of the bug.