Stupidity: Whenever General Grievous fights another lightsaber-user, there's almost always a moment with all the sabers crossed dramatically in front of both participants, one preventing the other striking a killing blow. Looks good, but utterly ridiculous, because he's got 4 arms and 4 lightsabers - he could easily block the blade in front of him with one or two arms, and simultaneously swipe at their head and legs, which no-one with two arms could ever defend against. Of course that would make for a lot of very short duels.
Other mistake: The battle droids - including the commando droids featured here - habitually have two broad fingers and a thumb. So how can a commando droid squeeze itself completely into clone trooper armor without its broad fingers tearing open the gloves, since it can't separate its fingers?
Mystery of a Thousand Moons - S1-E18
Obi-Wan: Very impressive. You just destroyed seventeen defenseless battle droids without suffering a scratch.
[Another battle droid falls apart.]
Anakin: Eighteen, actually.
Trivia: In S5-E1, Savage kills the Jedi with Obi-Wan. However, in S5-E2, she is sitting as part of the Jedi Council.
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Suggested correction: I know there was talk about whether this is a legitimate mistake or a trivia entry. The episodes were simply aired out of order. "A War on Two Fronts" was supposed to be the season premiere, but they ended up airing "Revival" instead. On the DVD, the episodes are ordered chronologically, and "Revival" is placed later between what's regarded on IMDb as episode 13 and 14.
Question: Did Darth Maul's return in this series cause big controversy among Star Wars fans?
Answer: I would say his death in Phantom Menace was more of a controversy. He was a fan favorite character from the movie, and his fight scene largely regarded as the best part of the movie. It was more he was brought back to please the Star Wars fans and few, if any, had problems with it.