In a Fafetch'd tale,the Johto one, Ash yells out, "Everyone, Razor leaf!" But only Chickorita did it. The others, Bulbasaur and Cyndaquil, did vine whip and flamethrower. As if a fire could do razor leaf attack! HA!
Hahaha .. I watched this episode and noticed it too, actually.
I didn't want to be too nitpicky about it, though. I like it, but rationalizers might say:
(1) Maybe Ash himself made the slipup and not the writers. Because Ash is so in-tuned with his Pokemon, Ash doesn't have to say, "Oops, I meant everybody attack!".
(2) It's only obvious what Ash wanted them to do; i.e. attack. How could non-grass types use razor leaf? Cyndaquil decided not to listen to Ash and do flamethrower instead, because cyndaquil was unaware of the mistake.
Semi-good slipup, in my opinion.