The main reason came down to running a 2D representation of an engine inlet and expecting to get the predicted behaviour in terms of water catch, evaporation and as a result, runback.
At the critical condition, a holding flight case, the engine stream tube capture ratio is less than one so the flow is diverging as it approaches the intake. As a result the cloud droplets move radially outwards and hence there is a net reduction of the liquid water content impinging on the intake lip.
The following figures demonstrate why this is so:
