I joined up 2 days ago, and I've just played my very first event - I used the Devil's Island one rounder from the Arcade section.
I played offline, and after reconnecting as advised at the end of the round (I read this thread before playing), I tried to submit the results half a dozen times, each time Links telling me there was a problem.
I've just checked the event scoreboard, and, sure enough, there I am!
(Okay, right at the bottom, but I knew that would happen! )
I'm a little loathe to try a multi-rounder though if this glitch will dq me from the subsequent rounds.
Hopefully this will be a one off. I have to go to a conference next week - but I might have time at the end of the week to try a multi-round event and see what happens.