Appreciate the help, Brad. If the Night Vision settings are on Auto, switch it to Manual. Then, manually toggle the setting on and off. Observe the feed to check if the pink or purple tint goes away when they toggle the Night Vision settings off. Also, unplug the camera from the power source, wait for 30 seconds, and plug the camera back in. If the customer has a Nest Cam (battery) or Nest Doorbell (battery), they must also restart their Nest camera or doorbell.
Let me know how it goes by replying to this thread.