Here's the official response from Page 13 (I think) of this thread ;
This explains how I was able to finish my HMP by going with my VW LS and alliance farming with 100% procs and 12~ people.Voidwatch drops are placed into individual loot pools, and drops increase greatly with more participants.
I have had far worse luck on solo drop rates.
However, even when I went with my friend's VW Static LS, we would often see the same person get five pouches in a 6-pop run, while another person was getting zero pouches in the same 6 pops.
So the problem remains, even if being in an alliance increases the overall drop rates, those drops can still randomly go to the one guy who was AFK most of the time, while the people who are spamming multi-weapon swapouts can be getting zero drops.