It is astounding how deluded in their blind defense of the game many people on this forum are.

The castbar/on-screen visual discrepancy OP brings up is an objective and indisputable flaw with the game. No one in their right mind would defend a game for having the on-screen visuals provide completely wrong information about what is going on.

In a non-MMO game, this would immediately lead to the game being deemed unplayable by most players. Of course due to the nature of online gaming some lag-related issues are to be expected, but when the cast bar DOES show the correct timing of the events and the visuals do NOT, that is plain inexcusable from a game design perspective.