How to reproduce:
1. Open the attached project "ShadowmaskBug.zip"
2. Open the "test" Scene in the Assets folder
3. Open Lighting window (Window > Rendering > Lighting)
4. In the Lighting window set the Lighting Mode under the Mixed Lighting Tab to Shadowmask and press Generate Lighting button
Expected result: The Point Light is bright and the static objects produce shadows
Actual result: The Point Light is very dim and the static objects don't produce any shadows
Reproducible with: 12.0.0 (2021.2.0b15), 12.1.3 (2021.2.8f1), 13.1.4 (2022.1.0b3, 2022.2.0a1)
Could not test with: URP 11.0.0 and lower - Deferred rendering is not available