Nikon issued version 1.01 lens firmware updates (LN) for the 20mm f/1.8 and 85mm f/1.8 to fix a problem where the camera might display an F-- and the viewfinder brighten briefly while autofocusing.
To perform a lens update, download the file, copy it to the root of a card, insert the card into the camera, mount the lens on the camera, and then use the Firmware update option within the camera (it should find the lens update if you do the steps right). The lens must be mounted on the camera to perform the update.
Nikon’s Z Lens download center
Also, the Viltrox 85mm f/1.8 has had a firmware update for the Z cameras (see here) and Viltrox has released lens profiles to use with the lens (see here).
