[jussij]

Thanks for the link. It is a very interesting read.

In particular it also says this:

To avoid both signals being added by the system, a priority P/B is provided on each stick. By pressing this button, a pilot may cancel the inputs of the other pilot.

From this link: https://en.wikipedia.org/wiki/Air_France_Flight_447

As pilot flying, Bonin took control of the aircraft via the side stick priority button and said, "I have the controls."

Which again suggests at least in this case, Bonin was the only one flying the aircraft.

[foldr]

Yes, indeed, I have not found any reliable source for the claim that both pilots were making significant stick inputs simultaneously for any extended period of time.