Continuity mistake: The bad guys are driving a dark green '62 Cadillac - with fins. After Five-O's sharp shooters fire at it, the Caddy hits a concrete wall. In the next shot of the wreck, the green '62 has turned into a black '64 - without fins. (00:42:45 - 00:44:35)
Continuity mistake: When Angela is talking to Sloan, her position in the hotel room chair changes back and forth noticeably between takes. (00:02:30)
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.