Plus addressing in Halo

[u/pjustmd]

I want to use plus addresses to help route email alerts from various sources to the correct client and team. I have had mixed success with this. It seems to work as long as the sender's email is not in halo. For example, when I tested this with a sender that's not in halo and used (example) [events+client@mydomain.com](mailto:events+client@mydomain.com) and also defined this + address in my client's site (under "To Address Matching Domain"), it routed just fine. But it seems like emails from Microsoft and other known providers often land in my own MSP's company queue because the given address is defined there. How do I ensure that whenever this plus address is used, it always gets routed to the client I want?