So I was battling the lass on the route between Mt.Moon and Cerulean City near the berries, and she sent out a level 18 Paras. It used Fury Cutter on my level 13 Sandslash and then I used Rollout. The next turn Paras used Fury Cutter again but missed, then Sandslash continued with Rollout, hit, and the game crashed. I think the crash is related to the fact both Pokemon were using power-increasing moves when used in succession, and Paras missing Fury Cutter screwed up something.

155512 So I was battling the lass on the route between Mt.Moon and Cerulean City near the berries, and she sent out a level 18 Paras. It used Fury Cutter on my level 13 Sandslash and then I used Rollout. The next turn Paras used Fury Cutter again but missed, then Sandslash continued with Rollout, hit, and the game crashed. I think the crash is related to the fact both Pokemon were using power-increasing moves when used in succession, and Paras missing Fury Cutter screwed up something.

Did you test again or just meet it only once? And also crash in your talk is about crash only game in your device or crash server?

The server has crashed indeed, but I do not think it's to do with the moves that you are using, that is more of a coincidence.