Deliberate mistake: After the Tusken Raider has attacked Luke, he raises his stick over his head and shouts. The movement of his clothing is extremely unnatural. During the editing, they put the same footage forward, then backward many times, to add emphasis to his movements, but it looks decidedly odd. (00:29:02)
Deliberate mistake: When Jar Jar gets arrested in the Gungan city, in the second shot of Jar Jar and Obi-Wan, Obi-Wan and a part of the floor behind him are reversed. This can be seen, for example, because two of the red areas on the floor have switched positions, and Obi-Wan's braid and lightsaber are on the wrong side. (00:14:00)
Deliberate mistake: The shots of the prisoner skiff during the transport to the Sarlacc Pit are reversed. This can, for example, be seen as Chewie's bandolier is on the wrong side, and that Han's shirt is overlaying the wrong way.