Clear Labyrinth Stage on Advance Summoner's Way

[Xentera]

I just try to clear every stage in Labyrinth with hard difficulty, but the mission "Clear Labyrinth Stage" wont complete. Is it bug or not? because its been 1 month i try to clear.

[Eshman]

Believe it or not I'm having issues getting that one to clear as well for some reason and I participate in every guild mission daily. If I'm not mistaken though it specifically mentions clearing it on Hard mode which even I'm having trouble with and I have 6-star runes with really great stats and several of the LD-5 mons from events/fusions/scroll pulls (no I'm definitely not bragging as I have to play almost purely f2p over many years w/hiatus XD).