Flip Flop joke lost in translation.

When they're in the car after visiting the medical school Oliver Stone points out the uniform and jokes by saying people wouldn't recognize Fidel Castro if he wore short, flip flops and an ugly shirt. However the interpreter mistranslated it as if Oliver Stone was referring to himself wearing the flip flops. Fidel didn't laugh at the joke (because what was translated didn't really make sense, or was funny) so Oliver Stone got a bit uncomfortable and said "It's just a joke. Does he not smile?"

Really a shame. It would have been interesting to get his reaction to that comment.