How to reproduce:
1. Open the user attached "yerp.zip" project
2. Go into File -> Build Settings -> Project Settings
3. Select the Player tab from the list
4. Set "1.jpg" as the Default Icon
5. Build the project from the Build Settings window
6. Navigate to the Build folder
7. Return to the Project Settings window
8. Replace "1.jpg" with "2.jpg" as the Default Icon
9. Build the project again from the Build Settings window
10. Navigate to the Build folder

Expected result: The Default Icon for the build is changing
Actual result: The Default Icon doesn't change

Reproducible with: 2021.2.0a9, 2021.2.1f1, 2022.1.a12
Not reproducible: 2019.4.31f1, 2020.3.20f1, 2021.1.25f1, 2021.2.0a8

Note:
* When changing the Default Icon through the Select button, the ".jpg" files may not appear
* To change the Default Icon, just drag and drop the ".jpg" files from the Assets folder