When integrated with OpenSceneGraph, some models load in a wrong fashion. Screenshots are attached. OpenSceneGraph alone renders the same models correctly.
This was tested using a modified version of osgQt ( https://github.com/openscenegraph/osgQt ), which uses QOpenGLWidget along with osgViewer::CompositeViewer. The same bug however occurs with Qt4 and Qt5 using QGLWidget as well (which is clearly visible in OpenMW-CS, another free software using osgQt).
The problem exists, when loading dae/collada models. When tested with fbx-model and osgt-model, the rendering is correct (although the model itself has a minor problem with non-applied mirror modifier). Perhaps OSG's dae-plugin sets some variable in a fashion that is not compatible with Qt4 and Qt5?
An example code along with modifier osgQt for CompositeViewer is at https://gitlab.com/unelsson/osgqt_tests/
This line (and the ones next to it) are for testing models in different formats: https://gitlab.com/unelsson/osgqt_tests/-/blob/master/osgViewerQt_CompositeViewer.cpp#L157