None of the sensors on the pump would cause this issue. It sounds as though the pumps are not backing off enough. The pumps are basically regulated by their own pressure. As each pump pressure rises, the delivery pressure is routed up to the pump regulators to back them off.
Are you 100% certain the engine is performing ok?
Does it look like any of the adjustment screws on each of the two regulators have been adjusted?
Have you done any troubleshooting on it with MPDr? Any fault codes, monitoring values, pressures etc??
Lastly, there's a torque solenoid fitted at the right side of the pump housing with a hose going to the right hand regulator with a link pipe going to the left pump. If the engine actual speed goes lower than the target speed this solenoid should activate and back the pumps to prevent engine stall. The higher the pressure from the torque solenoid, the lower the flow from the main pumps. Maybe worth putting a gauge in this line and reading the pressure when loading the hydraulics up. It should vary between 0-40 bar.