Earlier today, I was stuck in the middle of nowhere with a non-functional Viltrox 13mm f/1.4 lens on my Z fc. I had just upgraded firmware on the camera from 1.30 to 1.40. The camera simply did not recognise the lens and would not allow AF.
When I, frustrated and annoyed, returned home I rapidly found this was an issue with the latest firmware for Nikon Z fc, Z 30, and probably Z50 as well. The issue affected all my Viltrox lenses: 13/1.4, 23/1.4, and 56/1.4.
Thus my advice is: stick to your current firmware for these cameras if you use, or plan to use, any third-party lenses with electronic lens-camera communication. NB: this does not apply to the Voigtländer Z-mount lenses. As Cosina/Voigtländer apparently co-operate to use official Nikon technology, I got a sneaking feeling that Nikon silently have tried to pull the rug under other third-party offerings??
For Z 30: firmware 1.00 is OK, 1.10 is not.
For Z fc: firmware 1.30 is OK, 1.40 is not
I no longer have the Z 50 so cannot comment on that model.
Nikon immediately drops earlier firmware versions for downloading once the latest firmware is announced. However, either save the .bin file from an earlier camera upgrade, or get the required firmware from independent sites (do a quick search on the 'net).