How Do I fix this Dark Lighting on some of these props?

[MTD]

I have been making an edited version of Degroot Keep, however I can't seem to get these static props to not be dark, this only seems to really happen on the stone arch, base, and trim static props.

Does anyone know what I could do to fix these?

 

[Crash]

Doing full compiles with a few extra settings will fix that.

Here's a decent article explaining it.