Let me preface this by saying that I'm enjoying Shadowkeep and have been grinding pretty hard for my ideal PvE and PvP armor loadouts. One major disappointment, though, has been the Exotic Engrams given as seasonal rewards for leveling--there is apparently no duplicate protection, and moreover, they are seemingly not even weighted toward dropping armor over weapons. I just hit level 65 and have gotten my third Exotic Engram. 2/3 have been duplicate weapons--Hard Light and Skyburner's Oath--and as if that wasn't bad enough, they don't even drop at a light level higher than any legendary you'd pick up from the ground. In other words, they are literally useless. I dismantled them immediately. I believe this should be fixed quite easily by implementing duplicate protection and/or weighting the Engram toward rewarding armor instead of weapons (since Armor 2.0 drops with randomized base stats and most people will want to recollect their old exotics in their new 2.0 forms). Anyway, I'd like to reiterate that Shadowkeep is pretty darn good so far, but it would be great if Bungie fixed this small issue so that getting an Exotic Engram would actually be an exciting reward instead of the potentially worthless drop that it currently is now. Thanks.
Personally I've just decided to claim these rewards on my alt characters that I am missing certain Exotics on..I hope that this helps you..You can save just about all of your rewards from the Season Pass except of course the ones that "auto collect"...hope that this helps you out some fellow Guardian...Regards, Judge