i don't know if happens to me only, but if i enter in a station of the trial, i still have to select my lineup for the battle and i begin to talk in pm with somebody, i get always a 'request timedout' message, an immeidate call in pm by myself and if i click on 'confirm' for the lineup it doesn't let me start the battle.
At that point the only solution is to refresh the web page (and thankfully the game doesn't think you have actually selected the lineup so you don't lose any ninja).
Is not a serious problem, just a bit annoying.