I was playing showdown, and this guy was with an urshifu only. I lost because I suck, (lol) but in the middle of the battle, he changed from single strike to rapid strike. Is this a glitch?
I believe this is just a sprite thing. The sprite was a Single Strike Urshifu when the team preview showed, but it was a Rapid Strike for the rest of the battle. This is probably just due to both sprites not being added for the beginning bit when you select your Pokémon.
Hope this helps! :)