[KCO] + : The potential energy minimum is shifted significantly towards a bondlength of approximately 3.5 Å and there is a near-transition state structure at the reference minimum energy geometry. In contrast to [KCO] + , however, the stretching vibrational mode is strongly blueshifted with respect to the reference due to the sharp drop in dispersion energy close to a bondlength of 3.25 Å. Furthermore, the zero-point vibrational energy is therefore artificially inflated. The erroneous DFT-D4 gradients also negatively influence trajectories in semiclassical dynamics. Since these kinks are caused by coordination number changes, trajectories describing bond breaking or bond formation are especially affected. While both D4S and D4SL are able to remedy all of these issues, D4S provides a better equilibrium geometry in this example.