Mass of pure magic & ibedor's scroll

I don't understand a fact. I grind to star end for 7 hours in star end and mass of pure magic has a low rate to drop (1x every 2 hours). I don't understand why (that happening on hadumsha too) ?! but if i swap to hadumsha and i go to biraghi den (same ap like star end) i can get 7-10x per hour.
Same happening with ibedor's scroll (low rate). Summon with 3 friends 79x scrolls in first stage and no1 get at least 1 specter's energy after I would try again and just after another 40x scrolls, only one of us dropped an specter's energy (if drop for specter is so low idk exist any chance to get ember despair from this scroll - hard to defeat all bosses of the scroll but drop seems like a trash)