"Transgress" or "Go on Ahead?"

I'm reading in 2 John 9 this morning and see a conundrum between the KJV and the ESV. The KJV reads: "Whosoever transgresseth and abideth not in the doctrine of Christ." The ESV translates this phrase: "Everyone who goes on ahead and does not abide in the teaching of Christ." Weird. Is it "transgress?" Or is it "goes on ahead?"

BDAG says that when it is used transitively the word παραβαίνω means "to break or transgress." When it is used intransitively it means "to go aside." I wonder why the ESV chose "goes on ahead here." Mysterious.

At any rate, the key teaching here is that the best evidence of whether or not one "has God" or "has both the Father and the Son" is whether or not they abide in the teaching of Christ. This seems to be the gold standard of whether one is truly a follower of Christ or not.