I never say preventing scroll dropping. Instead of dropping something which I no longer needed, it's better to drop something which I need.
I think your scroll drop rate is messed up. Clan just did aff eb and not a single scroll drop. I think I have not gotten a scroll since yall changed it that no more duplicate scrolls get dropped.
Ever since the devs fixed the uneeded scroll drop bug the scoll drop for FS and TS have gone back to the old drop rate not the x3 drop rate the devs said they would make permanent.