If you have more than one Wireguard interface and try to delete one of them you get a Traceback, it works if I delete all Wireguard interfaces.
Traceback (most recent call last):
File "/usr/libexec/vyos/conf_mode/wireguard.py", line 311, in <module>
apply(c)
File "/usr/libexec/vyos/conf_mode/wireguard.py", line 225, in apply
cnf_descr = c['interfaces'][intf]['descr']
KeyError: 'descr'