I found a minor bug (perhaps maybe I am wrong) while playing 343 Guilty Spark on Legendary today. Once I got a shotgun and was in the latter half of the level, when I had full shotty ammo and came across another shotgun it gave me the option to swap my shotgun for a different shotgun. I am pretty sure you are not supposed to be able to do this. Just figured I would give you the heads up so maybe you guys and fix it down the line.