@JeremyECrawford if a player is a knowledge cleric double prof. bonus in history, then takes expertise in history is it a 4x prof. bonus?
— Extra Legs (@Extra_Legs) October 28, 2016
Take a look at the rule on proficiency bonuses (PH, 173–4). You can't double your prof. bonus more than once for a roll. #DnD https://t.co/Iq8oUIBbTH
— Jeremy Crawford (@JeremyECrawford) October 28, 2016