Currently all 3 say “destroy x set of blights on legend difficulty” I have ran it on legend 5+ times and nothing. The only quest progression I had was randomly receiving the quest for precision kills with the whisper equipped

If you're destroying the large blights in the rooms, they're the wrong ones. Theres a group of small blight in the spawn area for first quest Theres a group in the green jump puzzle room for second quest Theres a final group in the room right before you drop down into the boss room for the 3rd one - clear the room before shooting the small blights as people have ran into an issue that if you die after shooting one, it resets the counter and you need a restart Once you destroy a group of the small blights - its quest will update to the complete legend step

They say immune