(Insurgency: Sandstorm) Why do my "Production" quality shadows look so bad, even with a Lightmass Importance Volume?

Graphics settings have been maxed out both in editor and in-game. Adding a Lightmass Importance Volume appears to change nothing, and I have no idea what I am doing wrong.

Example One

Example Two

Example Three

Comparison to Powerplant: grass and shadows overall look as they should

Any help is appreciated.