When creating a Post Process material in 4.19 with a Custom expression that uses FScreenSpaceData, material editor is unable to compile, and material renders incorrectly. This does not happen in 4.18.
Result: Warning message appears saying material has compilation errors, does not render correctly in viewport as shown in attached screen shot.
Expected: See attached screen shots showing the exact same material setup in 4.18.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-54530 in the post.