Gaps of different colour in burnt DVD

I was wondering if there was something wrong with my DVD burner, Benq EW162I, or the Fuji 8x DVD+R discs I was using.

Some of the backup discs that I burnt when you hold it up the light you see gaps/holes/smudges that are of a different colour then the rest of the burnt disc. When you look at the disc before it was burnt everything looks fine.

Most Benq drives use WOPC which adjusts laser power and burn speed to achieve the best burn possible. It changes every few seconds during the burn. This might what you are seeing.