in mppicinterfoam, particles dont affect the interface

From what I know mppicinterfoam is a lagrangian-eulerian based solver where mppicFoam and interFoam are coupled.

So here is what I do for my master's thesis with Fluent.

I used DPM for air bubbles coming out the bottom of the geometry and VOF for water and atmosphere. Particles are injected at the bottom via cone-injection, and there is no patch for inlet unlike mppicinterfoam tutorial.

Then I moved on to mppicinterfoam, modified boundary conditions and stochastic tracking(which are assumed to be irrelevant to the issue that i'm facing) And the different thing from tutorial is that I set alpha of water to 1 at inlet so that i wanted simulate only particles are injected(velocity was set to the same as injection rate), and then it seems that particles alone dont affect the interface(surface) between the water and atmosphere.

my question is 'is this solver partly coupled?' , maybe I am wrong. But I really want to make this openfoam case at least similar to the fluent case. Please let me know what I need to fix. Thanks