Kamasa does not drop the hammer from Act 3 The Molten Vault Boss

so i got it on my main character im on my 3rd one and the reason for that is because on my 2nd one its bugged where the hammer doesn't drop... so now i have two characters that are STUCK on this and can't go forward with that quest. do i have to complete it or can i skip it since it bugged. just really annoying