"Draw Material to Render Target" renders black in 4.22
Confirmed in 4.23 MAIN @ CL 6395234
4.21 Repro project attached (Verify functionality in 4.21 and upgrade to 4.22 to repro)
4.21 Result: Render target material changes colors every second
4.22+ Result: Render target is black
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-74515 in the post.