I’m rendering a material to a render target on the render thread, the material renders fine except there are no alpha channel values other than 0. I’ve tried setting the material to be a Post Process material with alpha out enabled and I’ve tried Surface > Unlit > Alpha Composite Blend/Translucent/M…

Before doing the Draw, Clear the render target to 0,0,0,1 - and add a “1-” between the Mask A and the Opacity - that should get it working.