During testing I added a second wireless interface to the config with a different name but the same physical-device (phy) as an existing interface. The commit succeeded without errors but the 2nd interface wasn't added to the system. Then I tried to delete the 2nd interface but got an error:
[email protected]# delete interfaces wireless wlan1  [email protected]# commit [ interfaces wireless wlan1 ] Traceback (most recent call last): File "/usr/libexec/vyos/conf_mode/interfaces-wireless.py", line 1508, in <module> apply(c) File "/usr/libexec/vyos/conf_mode/interfaces-wireless.py", line 1383, in apply w.remove() File "/usr/lib/python3/dist-packages/vyos/ifconfig/vlan.py", line 68, in remove super().remove() File "/usr/lib/python3/dist-packages/vyos/ifconfig/interface.py", line 228, in remove for addr in self.get_addr(): File "/usr/lib/python3/dist-packages/vyos/ifconfig/interface.py", line 513, in get_addr if AF_INET in ifaddresses(self.config['ifname']).keys(): ValueError: You must specify a valid interface name. delete [ interfaces wireless wlan1 ] failed
Thus leaving me in a deadlocked state and I had to discard the config.
The reason I added the 2nd interface was trying to see if I could add a 2nd SSID aka virtual interface (iw phy phy1 interface add), but it seems that is not possible in VyOS.