I've found that this not a bug.
It happens because they applied the 300% Hot Time buff from the 3 scrolls sent to you daily from Striker Hot Time Event, which grants 300% more loot quantity. This stacks with combat and advanced combat buffs, goblin altar buff as well as pet skill effects. I'm getting >300% drop rate typically.
The others probably used their 300% hotline scrolls and you don't.