Question on wavy PSA background
 

I see some PSA holders have what appears to be wavy background around the cards like this:

http://www.ebay.com/itm/T206-Jack-Ba....c100506.m3226

Was this the holder for awhile or is it lighting?

(I just used the above for an example and I do not know the seller.)

It's a mylar insert PSA uses from time to time.