The Special Bulletin made reference to an error report within the cockpit display. Perhaps I might contribute a comment here, though surrounded by many ifs and mays.
Although FDR and CDR, known to the general public as Black Boxes, are not required items and were not fitted, use was made of maintenance logging within the other black boxes which make up the aircraft thinking apparatus.
This logging is intended purely for routine maintenance and might for example include a note that an engine has been used at 110 percent full power, or a landing gear oleo has suffered unusually high pressure, or a voltage is out of tolerance, or two identical fail-safe channels have disagreed by more than a certain percentage.
After a flight or number of flights these notes are downloaded and are used to assess what items have suffered stress or are out of limits and need maintenance.
In this incident the maintenance information has been very useful in finding out what has happened, though not exactly when it happened.
One item mentioned in the bulletin was a report from the display unit. The meaning of this report is not yet known. It does not necessarily mean that the display or any part of it was faulty, but simply that there was something out of spec, a voltage, a current, a data error, a disagreement between two otherwise perfectly functioning channels, or whatever. It could be a major fault, but equally it could be a very minor issue requiring some small item to be adjusted.
I guess I haven't added a whole lot of clarity here, but I'm an avionics guy and we never do. Hope this is helpful in some small way.