To better understand the errors in the intensities due to the PHVA approximation, we need to consider the truncation of the dipole and polarizability gradients, i.e., the removal of the derivatives with respect to the positions of nuclei in the solvent environment, as well as the fact that the gradients are transformed using the transformation matrix obtained from the partial Hessian. Hence, the origin of the intensity errors can come from the truncation of the Hessian and the truncation of the gradients. The total impact is reflected by the relative intensity differences. Since the environmental contributions are correlated to the expected changes in the transformation matrix, it is possible to identify for some modes if the high relative intensity difference is dominated by the truncation of the Hessian or by the truncation of the gradients. It is important to emphasize that we also consider the normalized absolute intensity difference, which is highest for the largest peak in the spectrum and expected to be considerably large for other intense peaks in the spectrum. Our focus 18 lies on considering cases where both the normalized absolute intensity differences and the relative intensity differences are substantial, as this indicates a visible difference in the final spectrum.