Ligand moving out of the binding pocket

GROMACS version: 5.1.4
GROMACS modification: No
Forefield: charmm36-jul2021
Ligand topology from Swiss-Param

Dear All,

I am quite new to Gromacs and I need help with result analysis.

I docked my ligand to the protein binding site and performed MD simulation for 50ns. However, I could see that my ligand is moving out of the proposed/docked binding pocket and binding to a 2nd pocket after ~20ns. This binding seems to be quite stable as seen from the RMSD of the complex, RMSD of the ligand, and also visual analysis of the trajectory. Does this mean that my ligand has affinity to the 2nd pocket (or the allosteric site) rather than the proposed pocket? Or am i doing something wrong during ligand topology preparation or MD simulation run?

Kindly advise. Any suggestions would be helpful.

Many Thanks.