Problem with pressure calculations during adsorption

[Temoor]

When I simulate the adsorption of my fluid on the mineral surface, I set up my external pressure to 1MPa. Now, I enabled the keyword of CalculateMolecularPressure. During the simulation, I get a pressure of 12MPa instead of 1MPa. I am unsure why it is not showing 1MPa partial pressure of my fluid.

I have tried the examples provided in the RASPA manual, and they give the same overestimated pressures during adsorption. What are the possible reasons for it? Am I setting the system wrong or the pressures are fine?