Rest In Peace, Somebody - S4-E10
Character mistake: Cameron's attempt to assassinate the governor fails because McGarrett has everyone wear bullet-proof vests. It's been established that Cameron is brilliant, a top-of-his-class ex-cop and a crack shot. And he's been sending death threats, so he knows they'll expect him. Yet he fires at the governor's back and is shocked that the man doesn't die. Anyone with his expertise would have anticipated the vests, and aimed for the man's head. (00:48:20)
Didn't We Meet at a Murder? - S4-E22
Character mistake: When Chin Ho reads Wellman's license plate number to the police dispatcher and repeats it to confirm, he recites a different number the second time. (00:30:05)
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.