[DEFENDER] Masking login area issue

After I install Defenderand set up new slug for masking login area, it affect all other subsites in multisite. By default my subsites user was using /wp-admin/.
Now they get message:
This feature is disabled
This issue exist in two cases:
1. when I create subiste manually
2. when someone register a site via Pro Sites

Pro Site page display two links at the end of process:

Your login details are:
Username: test
Admin URL: http://test.domain.com/wp-admin/

and
Login Now
I guess some cookie session exist there and when you click on it you're able to enter dashboard. After you log off the slug in URL shows the url you set up in Defender. Many users will not notice that. Next time they will use again /wp-admin/