Airfoilmode:
No, I am not suggesting that the suction system has its own fuel supply line. There is a short section of pipe that joins the main fuel supply manifold, via a check valve, just downstream of the LP tank pumps. I would not see fuel inertia as a problem there.
What I suggested was that air or gas that was trapped in the suction pick-up pipe might, under certain circumstances, become sufficiently pressurised to enable it to overcome the check valve differential and discharge like an aerosol into the main manifold. When this air/gas reached the engine HP pumps it would cause cavitation as the pumps ingested air and fuel supply to the engines would be reduced, similar to the situation where a diesel engine loses pressure at the injectors if air gets in the system. No doubt the LP pumps would have restored manifold pressure eventually, but in BA038's case there was insufficient time before the accident occurred.
Maybe the check valves have prevented this situation up to now and BA038 was the first unlucky one. Running a suction check from time to time would certainly remove any trapped gases in the system.