Received a Vanguard Mentor Missive today. Chose to go with A Light In the Dark. Right after that I figured I might as well complete the Summoning Pits Strike real quick and knock out the first part of the bounty. Now here is the peculiar part... Upon completion, myself and the other 2 random fireteam members all received the Depleted Hand Cannon for the first part of the bounty. At first I was like that is one hell of a coincidence. Then I started thinking about it a little bit more. My first thought is that the other two players probably had the same thought I did about knocking out the first part of the bounty real fast. That implies that we all received the same Vanguard Mentor Missive at about the same time and all happened to choose A Light In the Dark. This leads me to believe that the system clock (or an encoded "in-game clock" on the server side) is an obvious factor in what rewards you receive via RNG. For those who do not know, clocks are typically used to seed a random number generator to generate random results. The actual time of day at the point of calculation is often used to ensure that a number that is generated is "truly random." My theory is that at any point in time that you have received a Vanguard Mentor Missive, if anybody made that same interaction that you did (i.e. turning in a bounty with Eris Morn) within a specific time period, everybody that made that specific interaction within that timeframe will receive the same reward. I believe that this theory could apply to other instances of rewards as well. Perhaps Destiny had some sort of "RNG happy hour" (or happy minute) of sorts due to the way that the RNG is programmed. ....... And for the record, I don't think it is all about the time, I believe that the RNG feeds off of your statistics in various categories as well for other rewards. It's a combination of things really.