May be related to commit 3aefb5, dated 6 hours before this report, which bumped the revision number in the Portfile because the ICU library, on which the port depends, had changed. Maybe the buildbot has not compiled this commit for macOS 12 arm64. I do not know how to read the Buildbot UI to find that out. It seems to say that the builder for macOS 12 arm64 is idle, and has been for over 10 hours. That seems curious to me, so maybe I am not reading the UI correctly.
Also: fixed up the wikilink to a ticket's comment, in the Description above.