Originally it was excessive light bleed in the bottom left which makes any dark images in that corner invisible, I also have a bright pixel which falls under their premium panel guarantee so I should be given a new monitor. Considering I called exactly 1 week after receiving the monitor for a replacement and I am almost at the 2 week mark since my initial call I am getting furious. I am still waiting for approval even though my issue clearly falls under their warranty guidelines.
For clarity sakes, and less ambiguity, the focus of your need for a replacement only needed to centre on the bright pixel due to their next day replacement guarantee for such a situation. It is within their own warranty guarantee, as you know.
Going back to my issue I really did need to work a little at the beginning to prevent the agent from becoming too focussed on testing new cables and alternative computers to connect the monitor to, that was potentially a rabbit hole of side issues that would only detract from the monitor being dead. There was plenty that I purposely omitted. It got to the point of simply noting that the monitor with no cables attached, apart from the power cable, would not post or show any window message at all.
For you it is a matter of a single bright pixel and as such the monitor needs to be replaced, not much to do with the bleed.
I was lucky as I managed to get through to a very helpful agent, I got her full name and she gave me her own personal work email address. That came my single point of contact, can be difficult ringing them as there are so many options to go through.
Good luck with your return, hopefully you can get some movement on that. Dell are usually excellent in dealing with returns etc, in my experience.
In a sense I knew that a replacement meant going back into the panel lottery gamble, as to what would turn up. Thankfully the new one seems fine and has less bleed / glow than the previous one. It is all about compromise with a monitor.
It is the only piece of hardware that I do not look forward to buying....!