[jlund-molfese]

I'm seeing 10/10 though, with a custom iCloud domain ("Your hostname outbound.mr.icloud.com is assigned to a server.").

What's different?

[wildekek]

You got assigned a different outgoing server/PoP.

[jlund-molfese]

Interesting! I misunderstood and thought the issue was with every iCloud Mail server