Deliberate mistake: 9-12 "The Bells Toll at Noon": When McGarrett picks up Danny and drives away in his Mercury Grand Marquis, the rear view mirror is missing, probably removed to prevent it from blocking the actors' faces. It reappears later on. (00:33:00)
Continuity mistake: 9-4 "Man on Fire": McGarrett's blackboard already lists plutonium as the poison source before Dr. Ormsbee enters to inform him that plutonium was the poison source.
Factual error: 10-4 "The Friends of Joey Kalima": Guest star John Rubinstein (son of classical pianist Artur Rubinstein) guest stars as Joey - but his name is misspelled in the end credits as "Rubenstein."
Factual error: 10-13 "The Big Aloha": McGarrett compliments Palahana on his surfing skills with the line, "Nice ride." But the ocean behind them in the shot is virtually flat. With no waves, Palahana's supposed "nice ride" is impossible.
Continuity mistake: Stoner strikes Danno across the right cheek. But in the next shot, he's bleeding from the left corner of his mouth. (00:29:15)
Continuity mistake: Danno kicks one of the bad guys out of the van, leaving the rear doors swinging open. But when the shot immediately cuts to an exterior view of the speeding van, the doors are tightly shut again. (00:35:00)
Plot hole: Nadira hides from the bad guy behind a screen - with her feet in plain view. Then, after capturing her, the bad guy inexplicably lets her go, even though her knowledge poses a danger to him. Given that he's killed without a qualm before, this makes no sense at all.
Continuity mistake: 12-17 "A Bird in Hand": We see Angie take photos of mobster Del Vecchi with a 35mm camera. But later on, she develops the same photos and says she took them with a 110 camera hidden in her purse. She's a professional photographer and would certainly know the difference between 35mm and 110 film.
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.