Quantized Mesh: Height is set to zero first and then to actual height


when we load our quantized mesh it happens that sometimes the tiles will be rendered at - probably - zero height before rendered at the actual height. We also load many buildings and own image data.
Is that a usual behavior regarding the meshes height? As I mentioned this only sometimes happens. Is there any solution?


Is the problem that maybe the mesh is not loaded until the point of first rendering?