I have posted earlier on the pages and I stand on my thoughts:
The bank of 120 degrees he was doing abruptly with an increasing altitude is panic break away from a squall line storm cells - to me it looks that way. There were the cases in which hard banking of, let's say, 25 degrees in HDG mode could lead close to stall margins on low speed hi-altitude maneuvers like this on Airbus. Also, from my experience, some modern WX radars can be wrong - sometimes it will display and scan - nothing. Several cases are noted on 737-800 (but I do not know exactly which equipment is on Airbus) that radar was not displaying (or detecting, call it as you want) a storm cells or squall line storm. One of my friends (a captain on 737-800) was badly shaken because of WX radar malfunction. Aircraft was saved with proper CRM and procedures.
From my point of view this is a possibly stalled AC due to maneuvering in poor WX conditions. But you know that air crash is a combination of errors and events so every little piece of evidence must be carefully observed.
To introduce myself I was in former Yugoslav state ministry aircraft accident bureau of investigation (and ATC).