Residue no. changed after minimization

Respected Gromacs community,

I am trying to minimize a system containing 10 peptides where each peptide contains 7 amino acid residue and one ligand. I had the the residue no’s in a increasing order in the input gro file. After minimization the residue no’s of every ligand have been changed to 1. But it should be in a increasing order as it was in the input gro file. I didn’t understand why the residue no is changing and how to prevent that. If anyone can suggest a way to solve this it will be helpful.

Thanking You,
Bilash maity.

Could you include screenshots of the different .gro files you got over the course of setting up this simulation, along with the command you used to get to each .gro file?