I get this result in my own testing if I am in DX11 as the default RHI with Nanite enabled on this mesh. So it is probably the fallback mesh if Nanite is enabled while the editor is running in DX11.
I get this result in my own testing if I am in DX11 as the default RHI with Nanite enabled on this mesh. So it is probably the fallback mesh if Nanite is enabled while the editor is running in DX11.