mesh was deleted when load level??

hi there,
i created a new mesh, and used combineinstance to merge other meshs to this one,this worked fine,but when i used loadlevel to switch scene,the generated mesh was destroyed…like the GC deleted all the temp meshes when load new level, even i used DontDestroy function to make the GameObject persistent,the mesh still gone,

what should i do if i want to keep the runtime generated mesh when load level?

Are you calling DontDestroyOnLoad on both the GameObject and the generated mesh object?