The FCOM and FCOM doesn't explain properly the High speed protection. It leaves a doubt whether it supposed only reduce the acceleration or eventually supposed to resume climb even with stick held full forward. FCTM below:
Therefore, in a dive situation:
• If there is no sidestick input on the sidestick, the aircraft will slightly overshoot VMO/MMO and
fly back towards the envelope.
• If the sidestick is maintained full forward, the aircraft will significantly overshoot VMO/MMO without reaching VD/MD. At approximately VMO +16 / MMO +0.04, the pitch nose-down authority smoothly reduces to zero (which does not mean that the aircraft stabilizes at that speed).
The last sentence is ambiguous. It doesn't say it will climb (reduce speed)