Has there been any changes in 4.21 that require extra steps in order to get custom stencil to work for mobile, or is this a bug? Porting a project from 4.20 that had a post-process material using custom stencil stopped working in 4.21. I also created a 4.21 blank project to test this and got same results: SceneTexture:CustomStencil outputs a color value of zero instead of the custom value assigned to the object. This happens both when tested in editor with Feature Level ES3_1 and also when running on an iOS device. Feature Level Shader Model 5 works fine.
Post process material used:
Feature Level SM5 (works fine):
Feature Level ES3_1 (doesn’t work):
Same setup as above but in 4.20 and Feature Level ES3_1 (works fine):