These spots are points where the recording layer has been destroyed by exposure to air. I've been told by a manufacturer that this is commonly caused by the use of cheap or recycled polycarbonate(the clear plastic layer), poor manufacturing processes, or inadequate quality controls which ends up with microscopic "tunnels" through the polycarbonate allowing air to reach the recording layer at tiny pinpoints like that.
Too many people are reporting short life from their BD-R's. Another member reported a similar experience with Optodisc BD-R like yours. Thank you for reporting this. You may at least save some other people from going through this. I've been looking into this issue of BD-R longevity for a bit now, and I'm as disgusted as you are with companies that are willing to sell us this kind of junk.
Here is a picture from a recent longevity test with BD-R showing the same type of failure with JVC Taiyo Yuden BD-R. Don't worry about your burner, this type of failure is entirely due to the discs. And don't run out and buy Sony BD-R after looking at this. Sony also packages lower quality BD-R in some of their spindles.