How to perform molecular dynamics simulations of charged systems?
This is intrinsic to Ewald summation methods, not software implementations. The uniform charge arises from neglect of a reciprocal sum term. It does not directly affect the dynamics and may be a reasonable model of a spatially homogeneous system. See https://mailman-1.sys.kth.se/pipermail/gromacs.org_gmx-users/2015-October/101544.html for further details and https://www.mpibpc.mpg.de/14063977/Hub_2014_JCTC.pdf for a description and explanation of the likely artefacts.