## Summary When running Non equilibrium FEP, the perturbation from 0-1 fails due to "number of step" * "delta_lambda" != 1. This issue only exists in gromacs version 2022 ## Exact steps to reproduce Number of steps = 100000 1/"Number of steps" = 1e-05 ; Run parameters integrator = sd nsteps = 100000 dt = 0.002 nstcalcenergy = 1 nstdhdl = 1 free-energy = yes init-lambda = 0 delta-lambda = 1e-05 sc-alpha = 0.3 sc-sigma = 0.25 sc-power = 1 sc-coul = yes [NQ_A-3-I_0.mdp](/uploads/2c5849b64b34b2665bc1ad6a96a7a448/NQ_A-3-I_0.mdp) ERROR 1 [file MDP/X.mdp]: With init-lambda = 0 and delta_lambda = 1e-05 and no explicit input, coul-lambdas and vdw-lambdas will be greater than 1 after step 99999 of in total 100000 steps. This is not compatible with using soft-core potentials.