So, since the Dark Below DLC was released, I've noticed that Xur now can upgrade equipped Exotics. Normally, I paid no attention to that, since my total Exotic count across all characters is 4, but today, I noticed he could upgrade Achlyophage Symbiote for my Hunter character. Since Exotics take ages to fully upgrade, and I already had a spare Exotic shard along with 15k-something Glimmer, I thought I'd go ahead and do so. What I got, instead, was yet another disappointment - whatever upgrade progress the helmet had has been fully reset, meaning I've wasted the Exotic shard, along with roughly 7000 Glimmer. Good job, Bungie.