Murder with a Golden Touch - S6-E20
Continuity mistake: Danno reports that the salvage boat is "The Pacific Pearl." But when we see the vessel, the name painted on its hull is "Louise."
Continuity mistake: At the airport security checkpoint, Sam drapes a garment bag over the counter, but leaves after the inspection without taking it. Next shot, though, it disappears. (00:44:30)
Continuity mistake: Danno drives away from 5-0 headquarters in a 1972 Ford LTD, but arrives at the crime scene in a '73 with a distinctively different front grill. (00:04:05)
A Bullet for El Diablo - S6-E10
Continuity mistake: When Rita shoots him, Ramos dies face up on the floor, and she flees without touching him again. When McGarrett finds the body, it's lying face down. (00:20:05)
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.