Dragon render and QT3D out of sync

Several issues arise from out-of-order change event communication between QT3D and Dragon render aspect.

A minimal example is attached, where a datainput is used to dynamically change material diffuse map from an initial bitmap to a subpresentation after a presentation is loaded.

Expected result is that a static rectangle texture changes to a subpresentation that has an animating sphere. Actual result is a black texture, or more likely a null object/index out of bounds -type crash as changes in scene (creation of entities in the subpresentation, creation of other backend objects and so on) are cascading undeterministically down to Dragon aspect that initiates rendering for a new frame.

Null checks can be added to various locations in Dragon tasks and render functions to circumvent asserts/crashes, but this does not make the scene render correctly even in the consecutive frames.