liquid species

rubi

In a closed vessle (the computational domain) with stirrer, it is partially filled with liquids and rest is gas. In visualization plot, the liquid species showed up the occupation beyond the inter-phase boundary i.e. in the region that is only gas. Its mass fraction in gas phase, however, is 0.0 as set. In the model, there's also gas component but its mass fraction only showed in the gas region.

I didn't use free surface in this model. Should I??? Why the diffusion of liquid components goes beyond the phase boundaries?? Could anyone suggest a possible reason?

Thank you very much.