As established, the lightsabers of Shaak Ti, Eeth Koth, Pablo-Jill, and Roron Corobb are the weapons General Grievous ignites during his Utapau duel. However, a closer look at the fight itself reveals that the hilts Grievous is holding aren’t the ones that belong to those specific Jedi. First and foremost, one of the blue ones belongs to Obi-Wan Kenobi himself, while one of the green ones features the hilt synonymous with Anakin Skywalker (Hayden Christiansen). Grievous does confiscate their lightsabers earlier in the film, but both Jedi quickly recover them.
As for the other two, one is the hilt of Ki-Adi Mundi (Silas Carson), who is still very much alive during the Battle of Utapau. In fact, he’s on another planet entirely, Mygeeto, leading Republic forces against the Separatist droid army, blue lightsaber in hand. The fourth and final hilt is that of Adi Gallia (Angelique Perrin), who also previously lost her saber to Grievous only to recover it later. She meets her demise before the events of “Revenge of the Sith” on “Star Wars: The Clone Wars” during a duel with Savage Opress (Clancy Brown) and Darth Maul (Sam Witwer).
The most logical answer as to why the hilts don’t match is that it’s likely a result of simple digital asset reuse. Contrary to what the film itself might show, General Grievous’ lightsabers in “Revenge of the Sith” come from four specific skilled Jedi who, sadly, couldn’t overcome their imposing cyborg opponent.
