No Dynamic Shadows on Translucent Materials in iOS Preview

There are no dynamic shadows on translucent materials in the "iOS Preview" for the preview rendering level.

Working as intended in 4.16 CL# 3561208, 4.17 CL# 3658906, and 4.18 CL# 3832480.

Found in 4.19 CL# 4033788, 4.20 CL# 4212847, and 4.21 CL# 4221482

This is a regression.

1. Open the attached project
2. Set the rendering preview to "iOS Preview"

Results:
The translucent material will not have any shadow from the cube.

Expected:
The translucent material will have a dynamic shadow from the cube