I am puzzled that the media is widely reporting that the issue was caused by solar radiation, and that the immediate fix is to revert to the previous version of software for the ELAC (Elevator Aileron Computer). The only explanation that seems to fit with the narrative is that the newer version of software has weaker memory integrity checks than the older version - which seems unlikely.
e.g. "For the majority of affected jets, Airbus prescribed a software rollback to a previous, stable version" - from https://www.wionews.com/photos/-pitched-downward-on-its-own-...