After I got Blastoist mega stone I go for another one which is Venusaur Mega stone. I got Bulbasaur with correct IV but always loose to fight with Prof Oak. So I decided to give up and select option number three "to train other pokemon. When I catch Charmander with good IV and correct nature, I go to meet prof oak to show my pokemon. The the dialogue in the attach video happened. So right now I just have Blastoise Mega Stone. No Charizard or Venusaur because of this bug?!
Video - Google Photos.mp4