The wounded soldiers at civil war military camps aren't marked to respawn like the rest of the soldiers. It's possible this was an oversight like some other guards and soldiers in the game not having the flag. To be honest, I'm not completely certain it wasn't intentional for some reason. Like the quartermasters, I happened to notice that regardless of whether the civil war has been completed or not, they don't ever respawn like the other camp soldiers.
Templates: CWFortSoldierImperialWounded and CWFortSoldierSonsWounded