How to reproduce:
1. Open the “My project (107).zip“ project;
2. In the Project window navigate to Assets\Plugins\Win\x64 and click on Plugin.dll
3. In the Inspector window select Standalone platform
4. Change CPU from “Any CPU“ to “x64“
5. Press “Apply“

Expected result: CPU is “x64“
Actual result: CPU is “Any CPU“

Reproducible with: 2023.3.0a15, 6000.0.0b13
Not reproducible with: 2023.2.16f1, 2023.3.0a14
Could not test with: 2021.3.36f1, 2022.3.22f1 (“Any CPU“ option is not available)

Reproducible on: Windows 10, Windows 11
Not reproducible on: No other environment tested