since you can only get rewards for doing nightfall once per week, per character, and doing the raid twice per week per character (once on normal/once on hard) and with reports of the spirt bloom chests being a decoy rigged chest, I don't beleive that it is. Statistically speaking its possible, but unlikely. I believe that leveling up the Vanguard faction level 3 gives better drops in missions like patrols/strike/raid. plus the strike grimoire bonus card seems not to count strikes done through the vanguard playlists, or the weekly strikes. Wearing a faction mark in crucible tends to give me better drop rewards. Could be RNG, but I think that there could be a system. My tinfoil hat is firmly on.