Quest - Not A Toothless Dragon

[Nutri]

Hi
I'm having problem with Not A Toothless Dragon - https://www.wowhead.com/quest=42508/...othless-dragon

I can take and mount dragon but when we arrive at the bottom entrance dragon just changes his animation and i'm unable to talk to him ( complete ) quest from mage campaign.

More information how it should work is in the video on wowhead.

Server: Legion 7.3.5 x 11
Nick: Azarah
I'll be available from now till 1-2 am UTC +1 and tommorow around noon

EDIT: I manage to complete this quest by spaming right click on the dragon at the entrance to the cave BUT the next quest https://www.wowhead.com/quest=42521/...my-of-my-enemy is also bugged. I rescue Millhouse Manastorm but quest dosen't change to completed. I try to relog but dosen't help. There is no more dragon at the entrance so i can't pick up quest again (enemy of my...) any idea how to fix this?

Thank Youmag 2.jpg