Customized log-in screen dissolves into the standard Win log-in background - Help!

I use a Admin account that auto-logs in each time i start the computer. This is what i want and prefer.

But when i change the Lock screen and set the "Show the lock screen background picture on the sign-in screen" to either On or Off the log-in screen behaves in a randon way. It i set it to On it will sometimes behave as you can see in the video. I see the correct log-in screen only to see it dossolve into a standard Windows screen. I do not want that.

If i set the "Show the lock screen background..." to Off i get a black log-in screen and i like that. But, sometimes it stays black and sometimes it does also dissolve into the same screen as shown in the video. It´s the random behaviour with this that make it more than annoying.

I have noticed that one cannot just delete or replace the file img100.jpg in the folder C:\Windows\Web\Screen to brute force Win 11 in the direction i want. What i want is 100% custom log-in screen during the whole log-in phase or a black log-in screen during the whole log-in phase. I do never want to see any of the default log-in backgrounds.

This issue "only" happens when i cold boot the computer.

How do i solve this?

Video:

do you have a specific picture chosen for login?

if so try disabling login blur
disable sign-in screen blur
Computer Configuration > Aministrative Templates > System > Logon.
Show clear logon background policy enable

timbobit said:

do you have a specific picture chosen for login?

Click to expand...

Yes, a specific photo for the Lock screen that is reflected during boot and a picture for the account.

timbobit said:

if so try disabling login blur

Click to expand...

All blur and transparency are already disabled.

Hopefully i am on the right track now. The account had a password and i used the tutorial on how-to enable a passwordless log-on. So earlier this evening i decided to remove that password from the account. The next cold boot worked as expected. It has worked as expected earlier, so i don´t know if this was the solution, yet...