Incorrect/Different hard shading on meshes in Forward Shading

With forward shading enabled in 4.21 shading appears to be too hard on certain faces. This is working as expected in 4.20 CL# 4369336

Found in 4.21 CL# 4613538 and 4.22 CL# 4666322

1. Open linked project
2. Load the level "TestMap"
3. Look at the mesh placed in the level

Results:
The shading in certain areas is incorrect

Expected:
Shading on the same surfaces would appear the same as it does in deferred