One user on our install reports that `arc diff` to create a new revision (as opposed to updating an existing one) consistently fails with the error message:
> EXCEPTION: (ConduitClientException) ERR-CONDUIT-CORE: Attempting to access attached data on DifferentialRevision (via getRepository()), but the data is not actually attached. Before accessing attachable data on an object, you must load and attach it.
This appears to be returned from the `differential.createrevision` Conduit call, and is preventing the diff from being created.
Unfortunately, I cannot tell how common this issue is. The logs at /conduit/log/?methods=differential.createrevision show that almost every call is failing with `ERR-CONDUIT-CORE`, but many of those are due to T8455 and not this issue.
The full output of `arc diff --trace` is included at P1800.