After meeting up with April and Irma, Donatello's bandana changes to the color blue.
When Leatherhead first attacks the gator hunter, and his son in the Florida swamp, the color of his skin is grey but when he comes out of the water just before he mutates its dark green.
When Bebop informs Shredder that they got the turtles and the frogs after Shredder fell into the pool of water contaminated with mutagen, Shredder's outfit is laying on the ground in front of Leatherhead.