@bradfitz@radkat Not just Apple. There was a time @reneefrench bought a magazine with Google Books but it never showed up, and after calling support a helpful person told her, "Oh, that doesn't work. Sorry."
Actually I'll elaborate: @radkat just spent hours on the phone with Apple Support about how she never receives invitations to an Apple Home to her iCloud account or phone number.
It works for the other two people I tried sharing to, but not to her account.
After hours of useless debugging they said, "Oh, this is a known issue, engineering is working on it."