i have it too in the up-right corner of the screen and it doesn't disappear... it just get darker with hot screen and softens when it cools down
After 6-7 months of usage, same thing, in same place (upper right corner, don't dissapear - only getting bigger and darker on hot screen).
Took my phone to local warranty service, and after 1 week got call from this service - they told me, that service is REJECTED, because phone had physical damage! (WTF?!?!?!?! i haven't dropped it, and there is no crack's/spots of damage on phone!).
After telling them all this, and proposed that it may be glue, or faulty LCD/Overheat - they told me that LCD have crack from back side (?!?!?!LOL!?!?!?!).
Now i'm stuck deep in *ss, and don't know even what to do....
Anyone of you got solution to this problem?
Maybe contacting LG representives directly will help to solve this case?
10x.