As many people have correctly noted, Aberforth has committed Hidden Card Error and the penalty is a Warning. There is no longer an infraction called Improper Draw at Start of Game because it was combined into the new infraction Hidden Card Error. When delivering you ruling, be sure to instruct the players not to reveal their hands until you have finished explaining your ruling and what the two possible fixes will be. You could say something like: “Aberforth, you will have two options. First, you can mulligan directly to 5. After that, Bellatrix will decide on her 6 card hand and you will continue the mulligan process from there. The other option is to reveal these 7 cards to Bellatrix, and they pick one to be shuffled into your deck. Then you may choose to mulligan your modified 6 card hand and the process continues from there. Either way, you will still be receiving a Warning for Hidden Card Error.”