Hi Maddius,
It happens cause UCustomMeshComponent has no ENGINE_API in class declaration. But it creates some problem with linkage. As described here A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums It is better to reimplement UCustomMeshComponent.
- Add “InputCore”, “RHI”, “RenderCore”, “ShaderCore” to PublicDependencyModuleNames in CustomGame.Build.cs
- Just copy CustomMeshComponent.h/cpp to your custom project and replace Custom to somthing like Generated.
TSubobjectPtr mesh = PCIP.CreateDefaultSubobject(this, TEXT("CustomMesh"));