Was that 6 panels in a row before you got a keeper...?!
Is it possible to say where you got them from..? I'm a little wary of ordering another to try after having little success with my test of a VA panel Samsung UW at 34" or a 32" 4k which was faulty, as are most 32" 4k panels which use an Optronics panel.
Had a student discount for Amazon a while back, so ordered the monitor from there. Amazon just said they'd refund me, but I wanted a monitor. Asus only replace with refurbished monitors, but the process is very quick (around 2 day turnaround - they pickup your old one and replace there and then). However, they clearly have a warehouse full of sub par ones as I received the same monitor twice at one point (same serial number when putting it into their RMA site).
I finally got a good one, and sold it because it was more hassle than it was worth (I couldn't return to Amazon at this point). I got a call from the chap a couple of months after saying it had just stopped working, and asked me to sort out the return (I had given him a list of everything he needs to do in case of a return, with my original proof of purchase). I said if I get time I'll help out, but I'm in 9-6 most days at uni (except weds). He started ringing me every day asking if I'd done it yet, even calling from different numbers. Just blocked him in the end!
Anyway, back to original topic.
Monitor situation is in quite a poor state at the moment. You have to spend a lot on a professional monitor to get it defect free. Stuff like BenQ's pro series, maybe Asus' pro series (my PB278Q I still have doesn't have any backlight bleed).
Dell's customer service, from experience, is abysmal. If you're going to buy a monitor from them, get it direct, or you get a poorer quality of service from them.
It's why I haven't bought a new monitor. I don't have the time to go through the hassle of returning it every few days. Problem is I may have to - mine is on its last legs.