Regression in Draw Material to Render Target functionality.
Enabling Mobile HDR is a workaround.
Android tested with Note 4
Unable to verify Main CL 6395234 (Crash on Phone)
No repro on iOS mobile (Tested with 5s)
4.21 Test project with Draw Material to Render Target attached
Result: Material is blank in 4.22
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-74656 in the post.