There's a couple of glitches with the dragon stone that I have noticed. 

1.) Video glitch.. (unimportant) Dragon has yet to appear.

2.) Battle mode video glitch(unimportant). Cannot see opponent. 

3.) Battle mode force close (annoying). Engage the Invisible enemy and the game closes.

4.) Training selection force close (annoying). Happens when scrolling or during selection of the skill you want to train In.

I have already done the general fixes usually offered and have come to the conclusion that the problem is the game Itself.