yeah it is...i always wondered what kind of lightsaber obi had when he fought anakin(not vader) cause anakin almost wins the duel if he hadnt fallen in lava...
For distinction, I wouldn't be surprised if GL change dthe color of Obi Wan's balde to green for the "Greatest Duel of All Time" or whatever, but that doesn't run continually with his scenes with darth...
...Unless there's a third, DiFfErEnT lightsaber involved!!!!11one
I think it's just a coloring mistake and everyone is blowing it way out of porportion. It's a movie. Movies have errors. Nobody complains about ESB's potato asteroid field.