Hello,

I was shooting normally with my 5d and in between only 2 shots I noticed horrible yellow "tracks" on the LCD screen ( doesn't affect image at all!). It wasn't exposed to sun or pointed to it, actually it was in my hands...

Taking the camera and checking from many angles I noticed that it's something in between the glass and lcd... I took some different pics with different angles to show you...

You can notice that the lower yellow marks matches with the rough surface track on screen.

Now also white marks were noticed too...

Can you help me to find What caused this?

This is a polariser foil in LCD. Its thermally damaged, because you did burn it with concentrated sunlight like with an laser. Wievfinder attached to the camera is a loup. And its focused to LCD.
With something strong and wide open - like a 6X Cavision wievfinder you can do it within two seconds even on a winter day with sunlight.
Only Canon service can help you changing the whole LCD unit. I did it two times!

might be the the same for me, my camera is still under warranty will it be covered for replacement?