Nice Observation !!! 

You may block the update from installing again using windows show hide troubleshooter and wait for the next release. I am gonna test this tomorrow in the office and if required raise it to their Level 3 team. 

https://m.majorgeeks.com/mg/getmirror/microsoft_show_or_hide_updates_troubleshooter,1.html

Cheers! Please let me know if Dell will fix the problem.

Surprisingly my unit performed normally on both  versions. 

One thing which is different that I do not use Dell OS image on my machines as they have High RAM usages (around 3-5 GB ) idle. 

I had reimaged my Notebooks with windows stock image (media creation tool) months ago. 

Good day. I have pre-installed Dell OS and it definitly has this strange issue with the BIOS 1.9.2.

But thanks for the tip, I probably make a clean Windows 11 installation via Media Creation tool, when it becomes available.

I have another question to which you may have an answer. This XPS 17 9700 is missing an Unobtrusive mode. On my previous XPS 15 7590 was the (Fn+F7) function, which was perfect for disabling the display / sound when necessary.

Any idea how to disable (turn off) the display without going into stand by mode?! This was extremely handy option when working/watching smth on external monitor, don't understand why Dell got rid of it.

I reported it 1+ year ago, but no action unfortunately..

https://www.dell.com/community/XPS/XPS-17-9700-Unobtrusive-mode/m-p/7714348#M71320

Fn+F7 ?? I can't recall having this feature on XPS 7590

Fn+F6  Allows you to choose between different monitor modes.  

For any notebook (dell and non dell) Windows + P lets you choose between different Display modes when using an external monitor. 

This feature has to be enabled in the BIOS for the first time. Then you can press Fn+F7 to disable the display illumination (goes completely black) and turns off the sound. But it's not a stand by, etc., the PC keeps working normally and it's nothing to do with the different monitors.

I see there's the same complain about new XPS13:

https://www.dell.com/community/XPS/XPS-13-9370-Fn-F7-for-Unobtrusive-mode/td-p/6022826

So stupid that they removed it in the latest laptops, that was my favorite feature!

It was called: “Unobtrusive mode”.

I have been pulling out my hair trying to find out why my XPS 17 9700 has been running hot with fans on for no reason lately and it turns out it was exactly this. Downgraded my bios and now it's running way cooler.

Really disappointed by how little QA is going on with dell's software releases for this machine

Agree with Charles! It always a lottery with the DELL proprietary software and updates. Usually, no obvious benefits for the final customer, but more problems instead. I have scheduled a weekly backup of the entire OS drive with the Acronis True Image, as I had a situation when the Windows refused to start after an "urgent" update from DELL.

I faced the same System Process high CPU usage (~5%) BUT on a clean Windows stock image via Media Creation Tool. The CPU was constantly locked at a high frequency.

I downgraded to BIOS 1.8.2 and the problem has been resolved.

I did have to block Windows from auto updating the BIOS after this fix - I think it was by disabling UEFI Capsule firmware updates in the BIOS.

This has been my fist Dell laptop, and I must say, I am not overly impressed. This has just been one of the issues I have faced in the short amount of time with the device. One key problem is the laptop cannot cool the CPU adequetly. Why build a laptop that cannot take full adavantage of the CPU?