Reproduction steps:
1. Open the attached "case_1358687_hdrp.zip" project
2. Load SampleScene
3. Enter Play mode
4. Select the "Main Camera" GameObject in the Hierarchy window (XRRig > Camera Offset)
5. Change the "TargetEyeMask" value to None in the "TestTargetEye" Component
Expected result: the camera does not render to HMD
Actual result: the camera still renders to HMD
Reproducible with: SRP 7.7.1 (2019.4.29f1), 10.5.1 (2020.3.17f1), 11.0.0 (2021.1.18f1), 12.0.0 (2021.2.0b9, 2022.1.0a5)
Note: not reproducible with built-in render pipeline.