DDX and DDY no longer work properly close to the camera in 4.21 on Android in OpenGL ES 3.1. Worked in 4.20, no longer works in 4.21 or 4.22. Originally reported as Oculus Quest specific, but repros on Pixel XL in Open GL ES 3.1.
Does not repro on Oculus in -opengl mode or in -featureleveles31 on Windows, so seems to be Android specific.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-72140 in the post.