How can a Mavic freehub stop working after cleaning?
Here is the explanation to what happened:

The freehub bearing had been moved outside for about 2,5mm. When reassembling the hub, the body wasn't sliding as far in the axle as it needed to. Thus, the pawls were not centered in the notches and not engaging.

But, I did replace the freehub body and pawls first, and they were engaging. However, when placing a great force, one pawl eventually gave up and broke at an angle. 

Being able to see the angle of the fracture, I eventually deducted that the new pawls and freehub were engaging at an angle, so one end of the pawl was falling in the notch, while the other end was "higher", outside the notch.

I starting thinking about reasons for the pawls and notches not being aligned, which amounted to having the freehub not sliding far enough, and finally compared online pictures of the freehub bearing with what I have in hand. It was obvious that it was not pressed properly. After pressing in, the old freehub and pawls were installed and everything started working perfectly again, even the clicking sound got familiar again.