OpenMW-CS: Collada models are corrupted in Qt-based scene view

At least dae models often get horribly corrupted in the scene view. It seems that often most of the geometry is there, but renders as black, glitchy shapes, uv maps also may be wrong. I have tested this also with osgt/osgb and they might have the same problems, but this needs more testing.. OpenMW engine renders these correctly, so the problem is not in the component level.