what would cause a laser to mark CD's with circles

I would like to know what is causing my laser to make 2 circles about a 1/32 " from each other. I noticed this recently after a ring was removed from around my laser. Now discs are picking up this circle like indentation on their playing area near the center. One is now mistracking.
I stopped using the machine until I figure this out!
I had this happen...but more circles than you...it was a little spring that had sprung on the transport...as the sled moved across the disc was scratched...
Maybe the thin metal piece that covers and uncovers the lens as the tray goes in and out.Spring or piece has come loose protruding into the cd making circles.I removed the piece from mine and no problems.JD
This happened on my top load transport.
The plastic piece surrounding the laser was slightly convex.
I removed it and carefully applied a heat gun to it while pushing down in the opposite direction.
As it cooled, I continued applying pressure and it straightened, no more scratchy for me.