How to reproduce:
1. Open the attached “shader_variants_birp” project
2. Open the Build Settings (File → Build Settings…) and ensure that “Development Build” is selected
3. Press “Build”
4. Take note of the build time
5. Observe the result in the Console window

Expected result: The build takes a short time to complete (less than a minute) and few shader variants are generated
Actual result: The build takes a long time to complete (several minutes) and a large amount of shader variants are generated (30 000 - 60 000)

Reproducible in: 2021.3.39f1, 2022.3.31f1, 6000.0.4f1

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

Notes:

* Not reproducible in URP/HDRP
* The number of generated shader variants depends on the selected graphics API
** Direct3D11 - 50583
** Direct3D12 - 50583
** Vulkan - 33435
** OpenGLES3 - 32975