We beat Revan on Hardmode today, but the Encounter still seems bugged. The Force Lightning needs to be interrupted multiple times and before its first tick of damage. Even then, you need a tank who can survive at least the initial damage, which is something like 18k of damage or so.
Still, the game does not reward the group with the appropriate Hardmode achievement and the flashpoint also does not count towards the hardmode weekly.
Seems to me like one of the mistuned Encounters that are out there currently and need to get properly adjusted by Bioware.