Reproduction steps:
1. Open the attached file 'case867782';
2. Open the scene 'testScene';
3. Observe the scene window;
4. Open 'test' object in SketchUp program;

Actual result: in SketchUp program the object is invisible but in Unity - visible.
Expected result: the object in Unity should also be invisible.

Note: Everything works correctly if the object is saved as .fbx file. However, in https://docs.unity3d.com/Manual/HOWTO-ImportObjectSketchUp.html we wrote that Unity now supports importing SketchUp file directly into Unity. So it should work with .skp format too.

Reproduced with: 5.4.3f1, 5.5.0f3, 5.6.0b3