I just watched the subbed version of this weeks episode and noticed a few things I missed the first time watching it.
First of all, it looks like Alain got rid of his mega ring. You do not see it one his arm and even Charizard doesn't have it's mega stone.
Next, Ash makes a speech about returning to Kanto and "starting over from zero." We already knew this was happening, but further proof he's abandoning all his pokemon
Finally, when Ash suggests a rematch against Alain sometime in the future Alain thinks "I've always been saved by you. This time is no different. I cannot win against you." I did not understand this part at all, especially considering that Alain has beaten Ash not only during the league, but two other times. Of course he could be talking about Ash's determination or something, but it's phrased a little weirdly.