[UE-67936] Strange material bug

Hello, I managed to get this resolved.

If anyone’s wondering how, I clamped the Alpha’s of the two Lerp nodes (which wasn’t required in v4.18, v4.19).

However, I just noticed that the bug report for the above issue was marked ‘By Design’ yesterday (14th Feb 19) on Unreal Engine Issues and Bug Tracker (UE-67936) .

Can someone please explain what changed from v4.20?