The keyboard has a bright spot in the middle keys

I have a late 2011 MacBook pro I received as a giveaway. I upgraded the memory to 8 gig, upgraded the hard drive to a 240 gig ssd. Upon upgrading, I realized the keyboard has a bright spot in the middle keys. All keys are illuminated. It just has a bright spot in almost a v shape in the middle keys. Should I be concerned? Is there a recommendation? Replace the keyboard? Possibly some inning for me to check in the system?

The last 4 numbers of the serial number is DV13. The keys affected by bright spots:

5,6,8,t,y,u,g,h,n,v

Thank you.