Reduced amount of rewards on monsters on 5 way

Ive ran 2 5 ways with my friend, first 5 way we started on my atlas and there were no rewards on monsters at all, only on bosses, we started a 2nd 5 way on his device and there were rewards on monsters for only about a minute, and rest of the encounter only bosses had rewards, so not sure if this is some sort of a bug or what.