If it is a geometry issue，I think I find a solution, probably the problem comes from revit itself.
as mentioned the family component is fine (because it apears right when loading into a new scene), seems the problem comes from this scene only.
I saved the piano's family, then delete its deifination in the problemabic scene, then reload the family into it. It is fine now.
Thank you, Paul,
It is resolved
Supermicro 4028GR TR2|Intel xeon E5 2697 V3| windows 10| revit 2019 |Titan V+ Quadro GV100+RTX 2080 Ti