We evaluate the NAC vectors using the states' adiabatic wave function representation as computed by Ter-aChem. Adiabatic wave functions are, however, defined only up to a phase factor, which can lead to phase inconsistencies between different time steps. This phase inconsistency can also lead to a change in the sign of the calculated NACs, significantly affecting the resulting dynamics. In practice, TeraChem always uses real-valued state functions. Thus, during the propagation, the state functions (and the sign of the NAC vectors) can either keep their phase or change by a factor of -1.