Quite simply, the investigators KNOW what happened by now. The fact that there has been exactly ZERO airworthiness directives sent our to Airbus Operators would suggest that we can almost rule out Structural / Equipment failures and are more likely looking at a mishandled event. Investigators probably just trying to figure out what to pin on airbus to shift some of the blame much like the ASIANA investigation which concluded that the pilots were duped into crashing by a 'hard to understand' autothrottle.