didn't ame say before in another post somehwere that she's going to make it where some badges DON'T raise the level cap and instead only give stat boosts? so, we can never know how many gym leaders will all be within the same level ranges of each other before we get another badge that raises the level cap. in other words, being able to battle amaria could be in episode 15 or 16.
(for all we know the glitch field could have something to do with terra's gym battle. (something just for the shock factor?))
anyways, the next gym leader is probably either terra or ciel.
