Scene3D freezes up when change anchors

At some random step when I change anchor/anchors of Scene3D item it get totally freeze up, see example and video attached.

Example based on scene3d-loader qt example, I just add button that show/hide rectangle on the left side (like menu pane) of the scene3d and change anchor.left of the scene3d from parent to right side of rectangle (menu pane).

Sometimes in this example it needs about 20-50 clicks before Scene3D got frozen.
In my own, more complex project, it freezes within a several changes of anchors.

Scene3D freezes up with more enthusiasm on Anrdoid, or on desktop when CPU is loaded with other tasks too.

For this moment I've never got frozen Scene3D by just changing window size (without changing anchors).

qt 5.7 commit 8c1e1df4be02de8d64807d7abeccedc6becd3076