<< I had a green light arrow to make a left-hand turn, but got "jammed up" by cars ahead of me --- which meant I was then in the middle of the intersection, waiting to complete the turn, unexpectedly. >>
Well, in the two states I have lived, you're still clear to make the turn if you're in the intersection when the light changes. But, I'm not a Lawyer.
sounds like to me he was "trapped" in the intersection. i'm pretty sure that's illegal