I think it might just be a bug in 5.1 the alpha channel in the render target texture is flooded with white compared to a working cutout in previous versions. So scene capture 2d might not have the correct cut off values when capturing the information. Perhaps they changes something with the depth buffer that broke it?
Seems like I can get it working in Standalone Game but the RT texture is full transparent in pie and in viewport.
Had to switch the material from masked to translucent for it to start registering. Not ideal because it’s a larger performance hit
Material
RT Texture
SceneCapture2d (see nothing in viewport)
In Game works as intended
But it’s definitely not ideal. After these tests it probably something to do with the last updates to masked materials that they did for nanite.
They might have introduced a bug into the capture2d by accident or some overreaching optimization for nanites folliage.
Masked materials seem to be a big problem since most versions of UE 5.