When trying to edit a clone of a Panther-managed schema, a field whose name contains an ampersat character (@) triggers an error. This is strange, since the field seems to work fine in the original, Panther-managed schema.
To fix this error, edit the cloned schema and change the name of this field to omit the offending character.
This issue occurs due to a Panther bug, which we plan to fix. If you have further questions or interest in the status of this fix, please contact Panther Support.