I have purchased new Dell Inspiron with Intel UHD Graphics, I have updated to latest driver bot OS and Intel Drivers.
I have following issue - opening a website e.g dict.leo.org this is displayed correctly - but when cookie confirmation banner pops up this will darken entire display. Same behaviour when opening Intel Grafic Control Center.
Searching for that points to sensitive / adaptive brightness, but this is not source of issue as my system does not run any sensor that ist checking environment for light situation.
Looking forward for some hints
Are the drivers you are using released by Dell or by Intel? If you are getting your drivers from the Intel site, it is possible that you are running without customizations that Dell implemented and these may have something to do with this issue.
That doesn't mean anything. These drivers are all going to identify as being from Intel.
This is the important part: If you downloaded this driver from the Intel site (even indirectly using the Intel Driver and Support Assistant), then there is a chance that you have lost customizations that were added by Dell. In this case, you should uninstall the driver that you currently have installed and then reinstall the latest driver provided on the Dell site. If your laptop contains also contains a second graphics engine (from NVIDIA or AMD), the same applies there; use the drivers found on the Dell site, not the drivers found on the NVIDIA or AMD site. Only use drivers from other sources if Dell has specifically told you that this is ok.