Okay this isn't your regular increase adena drop topic. There is the actual problem with any drop at all when in party is character that is 6 levels above monster that is killed. I've encountered the problem on aligator island doing the daily quest. NOS has level 43 and when friend who has level 49 joined the party then said monsters stopped to drop anything. No adena, no materials even spoil FAILED 10 out of 10 times. Look into this and fix it. That may be the very core of the current problem of players not having any drops at all on farming zones because then have members in party with 8 leves difference which is the cause of missing drops. I asked said friend with 49 level do leave party to determine if he was the cause of missing drops and after he left the party we started to get drops again.
I'm kindly asking a moderator to move this topic to the bug reporting section.