so i just bought the 55 c7, and the 3rd day theres a red stuck pixel (not dead) that has been there even after few days. I don't think it is stated but was told the dead pixel policy is 7 pixels. in case you are like me thinking maybe it is not easy to spot a dead pixel in a 4k panel then ur wrong. due to its perfect black it is a head turner from 2m+. I think stuck is worse than dead. if you are thinking about extended warranty, its around 500 more.
Just sharing my experience cos not many hits on oled dead pixels. anyway they will be sending tech down to check on my unit.