If such differential transport has a divergence, then it will result in a change of the charge density, which will in return create an electric field that will alter the transport of one or both species in such a way that they become equal.
Then it will result in a change of the charge density. Such differential transport has a divergence. The charge density will in return create an electric field. They become equal. This electric field will alter the transport of one. This electric field will alter both species in such a way this.