Yes, because if the person moves to a new state, their entity has established a nexus in one state, and therefore that state exclusively governs them.

The business entity who has employees in other states is, by the exact same logic, subjected to the laws of each state they have nexus in, and an employee that is a resident of a state is transparently a nexus in that state, as you agreed upon in your "moving" example.

Hopefully it's clear!