With both HMR and SHAKE constraints enabled, we observed a clear correlation between increasing timestep and increasing energy drift. Specifically, for the cAMP system, increasing the timestep from 0.5 fs to 4 fs resulted in an increase in energy drift from 0.88 kcal/mol/ns to 2.8 kcal/mol/ns. The ethane system exhibited a similar trend, though with a more pronounced increase in drift, rising from 0.15 kcal/mol/ns to 15 kcal/mol/ns over the same timestep range. Notably, this general trend of increasing energy drift with increasing timestep was also observed when the HMR constraint was disabled, indicating that the observed phenomenon is not solely dependent on the application of HMR.