We should review the incident to an A-340 (with the same control logic) which experienced a zoom during cruise over the North Atlantic. While this was reported as an near-miss incident, the circumstances have unmistakable similarity.
The A-340 was in turbulence and entered alpha-protection which, with no stick input commands alpha-prot (about 4.2 deg at M=0.6). Achieving this resulted in a zoom of about 2300 ft (as I remember). The angle of attack reported in the latest BEA summary is about the same.
I'm traveling, so I can't refer to the report, but the incident was to A-340, TC-JDN on 2 October 2000. The report was AAIB Bulletin 6/2001.