Title : A bug with a character when trying to complete dungeon challenge 3.2

Device : My device is PC playing on Plarium

OS : Windows 11

WTR (way to reproduce an issue): 

Step 1 : Play the spirit keep dungeon on the lvl 7 or highter with the character "Lorn The Cutter"

Step 2 : Place an healing reduction debuff with the skill "Frightful frenzy" on the boss.

Step 3 : Kill the boss and complete the dungeon.

Step 4 : The challenge 3.2 which needs healing reduction on the boss doesn't seem to accept the skill "Frightful frenzy"'s healing reduction, probably because it gives also "Leech", so the mission is not completed.

Description : 

Like said in the step 4, The 3.2 mission dungeon challenge require an healing reduction placed on the boss faught in the spirit keep dungeon. But using Lorn the cutter and placing the debuff with him on the boss  using the skill "Frightful frenzy" doesn't seem to work for the mission.