VESSEL::GetTotalPropellantFlowrate returns nonsense

This seems like an API bug. when I call VESSEL::GetTotalPropellantFlowrate on my vessel with currently three thrusters at 10 kN each with 2000 m/s Ve, I get back pretty random values.

The returned values usually are in the 1e-10 range or even smaller, ergo utterly impossible. It seems like the problem would go away as soon as the vessel falls below an altitude of some 628-ish kilometers, although it still seems to fluctuate impressively.

Problem persists even with "complex flightmodel" deactivated (as I first thought it might have something to do with pressure. Still think it could, but not certain at all).