~~~ THIS SOLUTION IS SPECIFICALLY FOR THOSE TRANSFERRING ~~~
~~~ FROM A LAST GEN DIABLO III ROS SAVE FILE ~~~
For those who have earned this achievement [or trophy] in RoS on the XBox 360 [or PS3], the only thing you need to do to earn the achievement again is to gain 1 Paragon level log into a 'new game'. It does not matter what chapter or quest, but it must be a newly created start point. Change your main hand equiped item and this should pop for you. You do not need to level another Hardcore character to 70. Simply logging in on your 70 will not earn you the challenge or achievement. Earn 1 Paragon level and the game will re-verify your level status and the challenge and achievement will pop.