segfault at exit in View3D importScene test case

quick3d_lancelot/data/view3d/MultipleViews2.qml segfaults at exit.

It also has another issue; at runtime it produces the error:

MultipleViews2.qml:135: Error: Cannot assign [undefined] to QQuick3DNode*

that seems to be unrelated though, since removing the offending line does not fix the segfault.