VTK conflict with QT webengine...? [closed]

I ran into quite an obscure problem with the combination of VTK and a Qt WebEngine. Not sure if it is a QT or a VTK problem (or both).
To avoid double posts I link here to the post on the qt forum: https://forum.qt.io/topic/113362/qtwebengine-stops-displaying-when-undocked

Problem is confirmed to be Qt only.