It happens when being made I feel the colors just come out a bit different. Such as that Dunes Sultan blue $1 they usually had his tan colors not right on his body and the colors on the sword would be off. I know we are not talking the same issue here. Here we have different colors. I see there was some glue on there, could smoke or sun been the culprit to slightly fade the blue? Looks that the black is ok though but the blue might of been the first to go. I have seen light green chips left in the sun, turn grey! The whole chip- and some would think oh its a rare variant.
These weren't like U.S. coins they werent made perfect and Im sure were not inspected.

Nice Pioneer that is a rare one! Only have had one of those and dont think it was that nice.