Hulk Buster - S2-E11
Continuity mistake: When the Leader is talking about obtaining Mandarin's powers, the camera is focused on the ring on his finger, with Leader's face reflected in it. It then match-cuts to an outstretched finger adorned with a ring and Bruce Banner's face reflected in it. When the shot changes, Banner is holding the ring between his thumb and index finger. (00:03:24)