When implementing Drag & Drop to reorder the items inside of a List- or GridView it is possible to have the item randomly displaced inside of the view by releasing the drag outside of any drop area (100% reproducible). It seems that to Qt itself the item is still at the right place but rendered in a random location and a full redraw of the view (by resizing for example) restores the rendering. 

This bug can be reproduced without changes using the Grid Drag & Drop example as it is shipped with Qt Creator, so I'm only attaching a GIF displaying the problem.