The shadows on a spotlight flicker whenever the camera is moved.
Tested in 4.20.3 (CL - 4369336), 4.21.2 (CL - 4753647), 4.22.2 (CL - 6547378), 4.23 (CL - 6845209)
Expected: The spotlight renders shadows from the material
Result: The shadows flicker
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-75727 in the post.