Board Thread:Metal Gear Solid V/@comment-89.170.220.30-20151208145213/@comment-1504072-20151208151618

Presumable she would appear if the ceremony is unlocked before her departure in that partcicular player's game. The ceremony itself shouldn't be considered a canon event in the story, just a player-unlockable, so you are correct that it should be removed if it is discussed in Quiet's biography.