Godox V480 Flash Firmware v1.04 (for Nikon)
I just realized that a firmware update (v1.04) only for Nikon versions of the V480 flash was released recently by Godox. You can download the latest firmware for the flash from their official page here, as well as the firmware updater here.
This new firmware update only includes one change, and that is to improve operation stability by reducing flash misfiring with Z8 and Z9.
I did bump into some very occasional misfiring (i.e. flash not firing) when using the flash on-camera on my Z5II, but I do not know the exact cause or if it might be just user error on my side. I will update to this new version and see if it improves stability with the Z5II too.