The Face of the Dragon - S1-E17
Factual error: Two deaths by bubonic plague, spread by casual human contact, have Five-O scrambling to prevent an epidemic on Oahu. But the disease isn't spread this way (its vector is fleas on infected rats). And since the introduction of antibiotics in the 1940s, bubonic plague has been imminently curable, so there was no need for panic, other than, of course, to make the episode more dramatic. (00:18:00)
The Face of the Dragon - S1-E17
Character mistake: Near the end of the episode, McGarrett tells Dr. Kuh "The imposter Lewis Shen murdered your uncle." The uncle McGarrett is referring to was, earlier in the episode, referred to as Dr. Kuh's grandfather. (00:27:40 - 00:46:45)
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.