Masked Materials using the Forward Renderer and MSAA results in banded Gradient

Masked materials used in conjunction with MSAA and Forward Rendering results in a banded gradient which seem to correlate directly with the MSAA count variable.

This is connected to the Forward Renderer as the same settings within the Deferred Renderer do not output the same banded gradient results and works as intended.

Regression?
Yes, this does not occur in previous versions of the engine.

4.14.3-3249277 - Working
4.15.0-3299760 - Not working
Dev-Main-3315740 - Not working

1. Open attached project.
2. Bring up the console command (~) and type r.MSAACount 2

Outcome A banded gradient appears in the final material output.

Expected No gradient and a cleanly clipped masked material.