How to reproduce:
1. Open the attached “IN-75966” project
2. Open the “ApplicationTools“ script from the Project window (Assets/Game/Scripts/Tools/ApplicationTools.cs)
3. Add an empty line and save the script (CTRL + S)
4. Close the script editor and take note of the compilation time
5. Open the package manifest (IN-75966_MP-ECS/Packages/manifest.json)
6. Change “com.unity.entities.graphics” and “com.unity.physics“ to version “1.2.1” and save the file (CTRL + S)
7. Repeat steps 2 through 4

Expected result: The compilation time stays approximately the same before and after changing the package versions
Actual result: The compilation time increases significantly after upgrading the package versions (27 seconds to 210 seconds)

Reproducible in: 1.2.0 (2023.3.30f1, 6000.0.4f1), 1.2.1 (2022.3.30f1, 6000.0.4f1)
Not reproducible in: 1.2.0-pre.12 (2023.3.30f1)
Could not test with: 2021.3.39f1 (Entities not supported)

Reproducible on: Windows 11
Not reproducible on: No other environments tested