I've seen it only once , and that was with a playback unit that wasn't set on a straight angle , but rather some 20 degrees.
The thing is that the cd-rom scratches around its placeholders , thus leaving the ring in due time. It IS serious damage to your cd , but it can take a long time before the cd-rom actually gets unreadable.
I'd suggest to purchase some different brands of cd-r , write them on various speeds , starting with the lowest speed possible and check if the rings get any worse on them in time. Perhaps you can find some goog quality and writing setup policy this way.