"Masked" Shader always transparent in Forward Shading mode

Hello! Curious if anyone has hit this before, or if this is the intended result. But when I use a shader with “Masked” blend mode, and just pump in 1.0 into the Opacity Mask, it still renders semi-transparent. Should it not be fully opaque? I’m wondering if this is a side effect of using the forward renderer?

I have the same issue. Did you ever figure it out?

edit: Seems it only happens if MSAA is set to 8x. And there is an issue open for it UE-111048.