Okay, so here's a pretty strange/weird glitch/bug.:
I was playing Beta 2.22. I came up to Nalani, the fourth leader. My team was Bayleaf, Honchkrow and Swellow. I battled Nalani. The background turned totally black. That could've been done on purpose though. I sent out Bayleaf first up. Razor Leaf OHKO'ed Nalani's lead (not spoiling it). My Bayleaf leveled up to level 31. I taught it Body Slam then. Nalani sent out her second pokemon. I used Razor Leaf. The game froze. I loaded (thank god I had saved in front of Nalani), OHKO'ed her first pokemon and then I decided not to teach Bayleaf Body Slam. The battle went out perfectly and I won. Strange glitch, isn't it?
I loaded again after the battle. I went east to Atlanta Plains. I defeated the first trainer there. Bayleaf leveled up to 31 again and learnt Body Slam again. The game went smoothly after that. Even more strange.
Also, after defeating out the second trainer (a rocket grunt with Sandshrew and Sandslash) in Atlanta Plains, the game freezes with a pink screen. You can dodge him by going below him though.
Luckily, you don't need to solve the Body Slam-Nalani glitch because Chikorita won't even be in the next beta. :P
But you do need to solve that Rocket grunt-freeze glitch in the next beta.