Thank you for the response. Yeah I might need to return it. I just compared it to my 7 year-old Samsung laptop that also has a similar display (a non-reflective matte finish), there's no light leakage at all under the same condition. My other desktop monitors also don't have the same issue.

I too am facing the same issue on all the four corners. Also I do have a edge misalignment issue from left and right sides of the same 5509 laptop but they are listening. Just asking more and more images and videos of the issue, wihtout any plausible resolution and already have wasted a week of mine over phone calls and emails.

Dell INDIA Customer support is pathetic. Really shameful of them.

Here is the link to my post: https://www.dell.com/community/Inspiron/Manufacturing-defect-and-other-problems-arising-within-20-days/m-p/7824499

Did Dell accept it as a defect ? and  is ur return successful ?

In my case there is leak but in small portion and as per them it is a design. 

https://www.dell.com/community/Inspiron/5509-backlight-bleed-issue/m-p/7824419

Not happy with such a design, I have another desktop monitors and I do not see any leakage.

If is as per design then it should be uniform not just at one corner

Is the returning back of product successful?

These idiots day everything is as per design! 

Guys can anyone confirm if there is a gap between the lid and keyboard deck when the lid is closed??

Are you sure? Because my system has significant amount of GAP only on the front side, as if the lid is curved. Please confirm

Yes, bro it is there but no worries actually it comes into play when you put extra pressure on the lid when the lid is closed. It actually saves the display from harm due to flex.

I would say your backlight issue is on par with what I first experienced, and it seems you've got some IPS color glow on your top right corner as well! I'd definitely fight them for that replacement, if they still refuse you then send it back.