We tried recalibrating all our axes, but didn't make a difference. We'll try different brakes setups in the P3D settings to find if any works.
To Secondator: we are aware of that, but we determined the problem occurs independently of the parking brake use: we tried connecting directly on the runway to test this, both in takeoff state, and we started taxiing around the airport, and the brakes failed in two minutes time, without touching the parking brake in any way.
By the way, this happens on A330 ONLY when my friend is PF, but quickly extends to me when we switch roles trying solving the problem. I have Rudder Pedals with axis assignment, and he has button assignment on his joystick. We tried disconnecting each other's devices, but with no effects.
I hope some of this information could help you understanding the issue and give us the right advice.