Wow @goranb that is *exactly* my experience also; I have had some success changing USB priority from data to resolution which reduced how often this problem occurs during the day.

And yes MacBook Pro 16 M1.

Same problem with my 14" M2 MacBook Pro. It feels like it's dependent on the content displayed on the screen.

Is there anything we could do?

Same here. I tried everything and I think it's getting worse lately.

Okay I have a terrible terrible workaround that is foolproof (citation I am a fool):

1. Connect with to monitor with USB-C for power
2. Connect with USB-C to display port cable for display (shows up as second display)
3. Mirror the two displays in settings
4. Mess with monitor settings so Display Port is shown with KVM switcher assigned to USBC input

Using this configuration it is easy to verify that this is only a problem on USBC and not an issue with the panel. There is also one HDMI port left over for my gaming PC.

I have opened a support ticket and dell is sending another monitor; which should determine if this is a fault or a fundamental incompatibility.

Tip: An easy way to reproduce is to full screen the dell website, and select the drop down menus such as "support". It gives the correct ratio of bright white to dark to illustrate the problem.

The second monitor has exactly the same issue; also tried using the USB-C cable supplied with the each monitor to no effect.

The cable are marked both:

• HOTRON E246599 AWM STYLE 20276 ... USB 3.1 (printed on the cable)
• 2R4CW-AA20-24M Type C Gen 2A 5A (printed on a sticker)

Those are two different specs indicating the cable is rated for 1,250 MBps.

Based on reddit discussion I ordered an Apple Thunderbolt 3 cable (which the fine print has as USB 3.1 Gen 2) ... it offers the same flickering experience.

The problem occurs when using input color format YCbCr.

1) Using a second cable (USBC -> DisplayPort) causes the monitor to show up as a second monitor with RGB color space; cannot see a way to disable initial USB-C monitor.
2) Changing to USB-C Prioritization to High Resolution wile connected to the computer results in RGB color space
3) Reseting the monitor to factor defaults while connected sets to RGB color space

These workarounds do not last and must be done each day.

I also tried different USB-C cables but didn't see any improvement. The below picture/colour is resulting in flickering and odd lines on my screen when opened in the Mac Preview app and when clicking on the picture in my browser.

I have the same problem, using USB-C cable to my M2 MacBook Air. The flicker definitely is content dependent.

I am using the MonitorControl utility app to easily change display brightness via function keys. And when the flicker appears I can bump the brightness up or down a notch to make it stop (until some other content triggers it for that new brightness level). 

Seems like this is a technical design flaw with this monitor. So no point in trying to send it in for a warranty exchange. But I wonder if we should be entitled to return it for a refund during the warranty period? It is super annoying and not acceptable for an UltraSharp monitor (or any monitor really).

I am at my 2nd monitor as I returned the 1'st and the same thing happened after 30 min of use. I called in and now I'm going to receive the 3'rd one. symptoms: 

- screen burn in, even in self diag mode, although no cables are attached

- super annoying flicker and artefacts while using usb -c , hdmi or dp. 

- the fix someone marked as FIXING the issue, does not fix it in anyway, and even if it did, it's unacceptable to use this monitor at 30 hertz..this is clearly an engineering issue, and I assume this is commonly known issue, although no one bats an eye. 

1) Dell passed me over to apple support after sending a second monitor and troubleshooting over the phone. I also tried an apple "Thunderbolt 3 (USB‑C) Cable (0.8 m)" cable just to see if it would make a Difference. 

2) Apple cited U3223QE product description noting text under "A more organized workspace: Single cable USB-C connectivity offers the flexibility of connecting to multi-vendor USB-C systems (i), reducing cable clutter and enabling quick transitions from the desk." where the (i) indicates "Compatibility and performance with multi-vendor systems will vary." 

Also looked at dell support page which does not list U3223QE despite being updated in January 2023.

The conclusion amounted to DisplayPort being the correct way to connect the two devices rather than USBC.

3) I then had an interesting experience of being able to reproduce the effect ... using just the monitor on-screen display menu (wot?): see video

The video uses the USBC-to-DisplayPort adaptor, the color input is recognized as RGB, and the flicker is introduced just using the monitor on-screen-menu.

So I am not sure what to make of this? Not an incompatibility if the monitor can do it on its own...

Wow, there has been a bunch of updates since I posted this.

The other day I finally decided I don't care about the charging or hub capabilities of the monitor (the exact same things I actually purchased it for), so I switched over to HDMI to avoid the flicker. To my great surprise, it came back. For some reason it took it a few days, or at least I didn't notice it originally, but yeah, it's there, reproducible.

This basically means than none of the input options is capable of running the monitor without flicker: DP, HDMI, and Thunderbolt 3 are all affected.

One of the culprits I suspected was True Tone on Mac, but even when I turned it off the flicker returned quickly.

I fear I'll have to initiate return of this monitor as it's completely unusable for the purpose, but just in case anybody from Dell is listening: any other suggestions?