bug training poke using mega stone

[Fildc]

Hi, i was training my charizard using the mega stone to increase his offensive power, but there is a bug, because i got a lot of experience but no level increase, and the experience bar went over the screen, as you can see in the image. it happened more times, so it is a real game bug, I suppouse.

[Fildc]

i must add that after logging out and returning to the game the problem remains, so i have a charizard with a long bar of experience, that goes out of the screen

[Fildc]

the bar disappears when i win using charizard (base form) and i get all the experience that was cumulated before using mega stone. So, for example, using mega stone against a trainer, i accumulate experience for 2 levels but my charizard doesn't grow in level, but if in the next match i defeat a poke using charizard, base form, i get the experience of that defeated poke and the experience accumulated before, and charizard levels up, counting the two levels accumulated before