AO not affecting landscape

When I build the light, the AO gets baked perfectly on Static meshes, but not on my landscape (see attached image)

Am I missing some config, or is this the way it works?

My setup:

1 Directional light set to stationary

1 Landscape without any height sculpt (just a plane for painting textures)

light baked with high preset

thanks in advance!

I Forgot to mention that shadows are baked just fine! it’s just Ao that’s bugging me

I just wonder too. Seems Landscpe not support baked AO. I made some test and there is none of baked AO. It is probably dedicated for dynamic lights.