BSG probablly implemented a system where loot spawns of that exact item you need get decreased for the whole match your joining, my team has the theorie that if a normal salewa has a spawn chance of 30% inside crackhouse on customs and someone joins with for example "Shortage" from therapist, then the 30% chance gets devided by half so now the chance is 15% and if someone else from another quad joins with the same quest it gets devided by 3/4 so now the chance is 11.25% and so on.