I also have the Lincoln bug and fun to collect. Here's a few and one has a beautiful blue tone. What a great site, such fun with lots nice looking interesting coins.
It's just a reflection or artifact caused by the lighting. I used 3 lights. The beams were probably criss crossing and bouncing off the flashy proof surface.
This one just arrived at NGC for grading. Had it raw for about 7 months and used one of my free coupons too send it in. Nice detail on both the obverse and reverse. Some slight discoloration of the right side and carbon spots on both sides of the coin. I liked it and it was cheap. Will post the results when I get them
I had one of the reverse similar to PCGS along with a brown and white. I didn't get the full silver coverage on the obverse.