Been testing this for a few weeks now on my own. NO loot gathering, no PE's, nothing until I get all 5 chests. I hunt them down and open them with no regard. For 3 weeks straight I would have 3-4 cayde chests give me absolutely nothing (not even glimmer). Today, I had each chest give me stuff, like I was being showered in gifts for my perseverance. I did nothing different than I normally do. Straight to the Flashpoint planet and to the chests to loot. I hope this helps out with some testing or even lead to a possible resolution to the issue.