He was saying before that he thought Misty Terrain acted like Electric Terrain and boosted a type's moves.
I presume he found the source that mentioned it (a spanish review, I think? It was posted in the non-spoiler thread by mistake and it was edited out) also prevented stat changes
Exactly, but that source didn't say anything about the Dragon-moves, so I don't know if it's the same field-/weather-condition; additionally, it didn't mention Electric Field but rather a Grass field which we haven't seen as a move till now, so.. I'm holding my breath.