I have my MSI manager set up for topsoil stripping and respread. I have the topsoil set to usable up above. When I go to select landscape site improvement it does not show in my dropdown. I have to set up topsoil respread in site improvements(non-landscape) in order to see it in my dropdown. This requires addtional analysis and is not ideal.
Is it in your Earthen Materials category - it needs to be there before you can use it in Landscape - also has to be set to type Topsoil - if that isn’t the issue send me your MSI