Greetings, when you enable halfling luck in the character options and roll a double 1 on a check or attack both 1s get rerolled. see here (August 14 2020) PHB p173 : Advantage and Disadvantage : When you have advantage or disadvantage and something in the game, such as the halfling’s Lucky trait, lets you reroll the d20, you can reroll only one of the dice. You choose which one. For example, if a halfling has advantage on an ability check and rolls a 1 and a 13, the halfling could use the Lucky trait to reroll the 1. regards -Brt