Scene2D: Crash when changing item's size

The attachment contains a minimum example to reproduce this issue.

As soon as you resize the example window, the scene content (which is a white background) disappears. It also print 'Qt3D.Scene2D: void __cdecl Qt3DRender::Render::Quick::Scene2D::render(void) Fbo not initialized.' occasionally, and if you keep resizing the window for a while, it will crash finally.