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 lightsabre are on the wrong side.
Deliberate mistake: When Obi-Wan is fighting Darth Maul alone, after Obi-Wan cuts Maul's lightsabre in half, they start fighting on a different side of the pit. But after Maul kicks him, a close-up of Obi-Wan shows the wall and smoke of the area that they left. The shot has been reversed as well. The easiest way to see this is to watch his braid, which is on the wrong side.