If no nearby printers are present, ADD button on (2) becomes active when transitioning from 'Add printer manually'. That leads to 'Error adding printer' on black label at the bottom.

To reproduce:
1) On chrome://settings/cupsPrinters click 'ADD PRINTER'
2) On 'Add a printer manually' box, click 'ADD NEARBY PRINTERS' at the bottom-left
3) Observe 'ADD' button at 'Add nearby printer' box

Screenshot - https://screenshot.googleplex.com/vC8xyStMsmP