Quote Originally Posted by Arixtotle View Post
It's fairly simple. The cast bar and the telegraph do not happen instantaneously in the code by logical reckoning. When the cast starts then it triggers the telegraph. This means that the servers send at least two bits of information to the players computer at slightly different times. The route that information takes, along with any packet loss along the way, contribute to the issue.
And that is where we disagree. In reality neither of us can confirm which is correct, but why do you think the server would send two bits of information (the trigger for the castbar and telegraph) separately to the player's client rather than as one single event? To do otherwise would be just asking for problems.