Foliage won't spawn on landscape after migrate

Hi guys, I’ve got a problem with foliage system in UE5.3.2. I’ve got a my level with landscape, some external objects (fbx mesh) and foliage painted on landscape and meshes. When I migrate that to another project, everything work’s fine, but the foliage not spawning in the landscape, but only in objects. Landscape is already painted, all the objects have a material. When I migrate level to another project, I migrate just a content folder and after that I’m just drag&drop my sub level to the main one. When I going to edit my sub-level inside my main level I can see for just a one second that missing foliage appear in correct place and after that dissapear again. I have no idea how to fix that and where is a problem. Could you help me with it, please? Thanks!