Rob
Ansys Employee

Inflation is less critical with VOF, what you need is a nearer to aspect ratio 1 mesh. If you have an excessively fine near wall resolution and coarser core mesh then the solver may damp/lose mass. 

With a high aspect ratio cell the assumption is that the flow doesn't change along the cell. With multiphase free surface (and flow separation in high speed flows) that isn't true and you can't then have such a high aspect ratio. Coarse core mesh will similarly damp things. Remesh with a fairly fine and reasonably uniform cell size and then look into dynamic mesh adaption: there's a VOF option in 2021-ish and onwards.