Our diagnostics ruled out several common explanations for a directory that would not accept an ownership change, without pointing to a new one. At that stage we chose a fix that does not depend on understanding the cause: if the ownership is still not as intended after the normal repair, the directory is replaced with a fresh one. The directory held nothing worth keeping, since nothing had ever been able to write there.
We then applied it to a test server to check the result. The lesson: when diagnostics stop producing answers, a clean replacement can be the pragmatic route.
Tested (2506/2506).