I bought brand new U2415 ,and there is some kind of shadows in the corners i guess is from the backlight . Can i exchange the monitor under the warranty policy ? I saw one very similar post to mine here , but i decide to ask just in case because if i can`t that will be shame . For much lower price i can buy TN monitor which for sure will not have any shadows , i`m working with that monitor after all.
Run the monitor Factory Reset, Self-Test, BID (Built-in Diagnostic) per these instructions, which remove the computer and cabling from the troubleshooting. Do you see the issue when running the tests? If yes, get it exchanged.