"sylvactl -n xxx" fails with "namespace specified with -n ... does not match namespace in resource identifier"

One of our Sylva 1.4 users ran into this:

$ sylvactl watch -n sylva-system
Error: failed to determine namespace: namespace specified with -n (sylva-system) does not match namespace in resource identifier ()

This is related to !391 (merged).

The same things works on main (!357 (merged)), so there must be a difference which makes it fail with branch release-0.7.