HRD Redirect Affecting All Organizations with Same Email Domain - Expected Behavior or Misconfiguration?

I’m using Organizations with Home Realm Discovery and Identifier First authentication profile. I would expect the HRD to only apply to organizations where the given connection is enabled. However, when I enable the connection for only one organization, logging in as a user from any other organization (with same email domain) immediately redirects to the enterprise sign in page even though the connection is not enabled for that organization.

Is this the expected behavior or do I have it misconfigured?

This wouldn’t normally be an issue for orgs with different domains, but our enterprise connection’s domain is the same as our team’s email domain so none of our admin accounts are able to log in when I enable the connection because they are directed to use the enterprise connection instead of username/password.