When Bomba teaches David how swing on the vine, they push off from the tree limb with David on the left and Bomba to his right. However, when the camera angle changes to a closeup of both swinging side-by-side, David is now on the right of Bomba. In this view, it would have meant that they tangled their vines and physically could not have swung together.
During the volcano, in one repeated shot of Bomba and the others, the immediate foreground is shaking while the background is unchanged.