Are your friends raiders as well? Raiders will sometimes be clearing ToS on all the settings pretty quickly on raid or off nights, Mythic+ keystones, daily caches, then recompense which can be racked up super quick by nether portal farming during when the disruptor is active.
edit: Hell I'm not a raider and I get one every two weeks from doing LFR ToS, normal Nighthold, Mythic+ farming, daily caches, and nether portals.