Continuity mistake: McGarrett's left hand rests on the side of the large multi-line telephone as he makes his call. The camera angle reverses, and his hand instantly jumps to a different position, resting on top of the phone. (00:41:00)
Revealing mistake: When Sally is driving the blue station wagon full of singing kids, several light reflections on the side of the car never move at all, revealing that it's really a stationary mock-up sitting on a soundstage. (00:42:30)
Answer: He was fired. He never really appreciated his character. He felt Kono was portrayed as a big dumb Hawaiian and that the stereotype was racist. He also felt underutilized. He was fired after a heated argument with the show's publicist regarding his character. It seems there's not much details given regarding the incident or the firing, so it's seems possible he upset the show's producers as well.
Bishop73
No he said something derogatory about one of the Jewish producers that's why he was fired.