Windows 11 Doubling startup background picture

This Is Normal Windows 11 Behavior​

Zevik83, you are seeing two separate stages rather than a duplicated startup screen:

1. Lock screen — displays the background, clock, and date.
2. Sign-in screen — appears after pressing Enter and displays Enter PIN.

Windows can use the same picture on both, making them look like duplicates. This is a Windows 11 design choice, not an ASUS/ROG fault.

Make the Screens Look Different​

1. Open Settings.
2. Select Personalization > Lock screen.
3. Turn off Show the lock screen background picture on the sign-in screen.

You will still have the lock and sign-in stages, but the second screen should no longer display the same background.

Correct the 12/24-Hour Difference​

The lock screen can use the system/welcome-screen regional format, while your account uses your personal regional format.

1. Open Settings > Time & language > Language & region.
2. Confirm that Regional format is set to your preferred region.
3. Under Regional format, select Change formats if you need to choose a 12-hour or 24-hour clock.

Then copy that format to the welcome screen:

1. Press Win + R.
2. Enter intl.cpl and press Enter.
3. Open the Administrative tab.
4. Click Copy settings.
5. Check Welcome screen and system accounts.
6. Click OK, then restart Windows.

After restarting, the time format should be consistent. Nothing appears to be wrong with the laptop based on your description.