Black-purple line near edge of disc?
 

Hi, I was burning about 100 or so discs and noticed 5 or so have this black or purple looking line near the edge of the disc. It's sort of a half circle shaped. Copying files from the disc, read, scan, and quality tests look fine, so I wondering what this could mean? I attached a picture, although my camera isn't the best.

Probably missing dye, or dye defect, or dirty disc when burned, not good, bad burn or disc.

What brand discs?

If the burns tested good, how much content did you put on them? You might find trying to use 100% of the rated capacity disc doesn't work, that you only have say 96% available for content before burn errors.