Relaxation alongside minimize command or without it?!?

Dear Lammps users,
Hi! I hope all of you are fine!
I have 2 sample. one of which is pure Al and anothers is an alloy including (50%Al-50%Cu). Now, I have a question!?!
I relax my samples in NVT&NPT termostats without “minimize command”, Having said that, when adding “minimize command”,the pure one endures constant but (stress-strain)'pick point of alloy one is being greatly changed! How can justify this?

Thanks,
Nili