Other mistake: During the scene of the Bone Dance in the castle, Daniel shouts out "Behind you!" to the Japanese girl as Chozen grabs her. As he does so, the shot goes wide and you can see Daniel and Mr. Miyagi rise up and begin to run forward. The shot then returns to just Chozen and the girl, and when the shot goes wide again, Daniel and Mr. Miyagi are again just getting up and running forward.
Continuity mistake: When Chozen moves at Mr. Myagi with the spear, when Mr. Myagi grabs the spear the first time, he places it between the 2 pieces of wood, but then when Chozen picks it up to attack him a second time, the spear is to the left of the 2 pieces of wood, in the ground.
Revealing mistake: In the fighting scene when Chozen has Daniel choking on the spear, before Myagi appears, the first person was standing on the deck to the left and throwing plants through the hut, but then Myagi comes and all of a sudden, he comes at him from the right. Somehow he made it from the left of Myagi to the right of him without anyone seeing him.