Just to be clear: I’m not talking about possible +% health/shield/armor random modifier that can show up. All mayhem modifiers are decided on when you enter the map, and displayed beneath mayhem UI plaque on map screen. But I’m talking about info written inside that plaque, aside with +30% exp, +60% cash/eridium and +300% loot.
Far as I understand it displays base effects of a mayhem mode active, before any modifiers are thrown in (those are displayed beneath main plaque). And it does contradict that “Mayhem information” button.