You may want to contact Bridgestone for piece of mind. If it were me, I'd have no issue in running that tire. The line is not straight around the tire which makes me doubt it's the separation point of the two compounds. I suspect if you keep an eye on that mark you'll see it disappear within the next couple hundred miles.
When you decide to replace your tires, if you like your Bridgestone BT016's then I'd suggest you stay with them. Bridgestone makes good tires and the BTO16 is a great tire. I've run out a number of sets when the 16's first appeared. Great grip, sweet handling, and decent mileage. Your busa loves consistency. Bouncing around between tire manufacturers never lets you maintain front end feel. My theory is: Stay with the same family of tires for a full season to avoid chasing the sweet spot. Different tires usually take different suspension settings. For the advanced rider, front end feel is just as if not more important that outright grip.
With that said, I would suggest considering moving up to the Bridgestone S20 which is the next generation of the BTO16.
My favorite tire currently available today is the Dunlop Qualifier. The current model is the Sportmax Q3. Amazing tire in the same family as the BT016 & S20. Prices are about the same.