U2421E, light vertical lines

I can confirm the exact same issue. I've also bought two U2421E which are connected to a desktop PC via DisplayPort and to a Dell Latitude 5491 via USB-C. In my case the vertical lines are noticable on both monitors. And as already said, it only applies to blue and orange colors. I couldn't detect any issues using the built-in diagnostics.

I made a picture and overdid the effect in the top half, to show which lines are affected. As stated above, it seems to be every 2nd pixel column on my monitors:

The effect is barely noticeable in the image above but somewhat annoying to the naked eye.

Anyway, I'll return the monitors and already ordered two EV2495 instead. Maybe if Dell can fix this, this will be a great monitor someday.

@new_userA little off-topic, but: have you received your EV2495 yet? Today I've got one (out of two ordered) and it looks like it has the same issue. I've tried DisplayPort and USB-C.

Doesn't sound good, especially at this price tag. Maybe they use the same panel? I'm awaiting mine any day now and report back once I get them. In the meantime I looked for this behavior in other IPS monitors but noticed in on none of different brands..

Seems to be a problem with some LG panels:

https://www.dell.com/community/Monitors/U2414H-vertical-lines-in-blue-and-orange-color/m-p/5091995

https://www.dell.com/community/Monitors/U2414H-vertical-lines-in-blue-and-orange-color/td-p/5141001

Unfortunately most vendors don't specify which panels are used.

Just received my U2421E today and it has very distinct vertical lines in blue and orange, thinking of exchanging it for another one hoping that I can win the panel lottery if I try again

Received them today. Only tested one of them, same issue. But thanks for the hint, if not for your repy I would have set them up first before turning on..

How did you decide?

Have you returned them? Today I've talked to EIZO support and I was told that it's an issue with the 24,1 inch panel and the 16:10 format. And I was recommended to return the monitor and get the 2795 instead which shouldn't have the issue. I didn't expect that answer, but okay.

Now I think about ordering the Dell U2520D instead.

Received one U2421E the other day through Amazon having the same panel issue.

It would be an awesome monitor without the issue. Did Dell acknowledge the issue in the meantime?

Dell said via private messaging that the pictures aren't enough and this effect might only show on the taken image - I should instead make pictures of the whole screen. As it's not really visible on a picture of the whole screen this obviously wouldn't help. Me stating that the effect visible in the picture is also visible in real life didn't really change much. 

Instead of wasting too much time I sent the screens back and ordered others. Unfortunately the Eizos had the same issue as stated before. As 16:10 isn't really common and a lot of similar screens share almost the exact same specs I guess most use the same panel. So instead of trying yet another 16:10 I'm now on two P27h-20. They are much bigger than I'd like and I gladly would have paid more for a good 16:10 24" pair. But at least I now have the expected image quality without any strange effects as one would expect from any monitor marketed as "premium".

Maybe it's worth to wait some time but if you want to buy now I'd stay away from this screen size. The Dell U27.. might actually use the same panel as the Lenovo but I'd rather like the monitors without the logo on the front.

Sadly anything bigger than 24" and 16:9 is not an option for me, which reduces my options dramatically. Most likely it's LG that messed up this particular panel series and which they supply to the other brands as well. I wonder how QA hasn't stumbled over such an obvious issue. I submitted a review to Amazon pointing out the issue and to increase the heat.

There seems to be one other panel from AU Optronics with similar specs (M240UAN02.1) which is used in the ​BenQ PhotoVue SW240 for example.

With manufacturers keeping it a secret which panels they use this almost makes it a gamble.

Received a 2nd monitor that still had the issue with vertical lines in blue and orange and also had a bright pixel, just received my 3rd replacement which also has this issue, the first 2 monitors were manufactured in September and the latest monitor was made in November.

Two days ago I bought a Dell Ultrasharp U2421E monitor and found exactly the same problem: light vertical lines in blue and orange.

Absolutely disgusting quality in premium products. I returned it back to the store.