I just competed a 3 hour master run and got the exotic. However, my engrams were full and it did not end up in my postmaster. It is not unlocked in my collections and it is not in my recent discoveries. My postmaster was not full.
Hey there. Did it actually show up in your feed as Hierarchy of Needs, or as an Exotic Engram near the chest? If your engram inventory is full, then the enhancement material that can drop from the Master chest, shows up as an exotic engram in your feed, as for some reason some of them need a free slot to be picked up. It can also happen if it's an Enhancement Prism and you are full on them already. A genuine Hierarchy of Needs drop goes directly into your Energy Weapon slot, it does not require an engram slot free, and does not drop from the chest, it appears when the boss is killed.