1. Create a simple project.
2. Add several static mesh actor to a level with the masked material.
3. Package and launch the app on a PowerVR GPU device.
The GetSortMode will return EBasePassSort:: None, but the masked primitives should be sorted because the MTK engineers reported that the "discard" instruction would break the early z pipeline.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-66834 in the post.