Okay, this is probably better entitled "Stupidity on My Part". If you have multiple zephyr servers and forget to put the keytab with the zephyr/zephyr principal in the proper place, they can't talk to each other. The symptom of this is your zephyr servers constantly trying to braindump at each other, and failing. Once I realized I had forgotten to put the keytab as well as the srvtab in the proper place, everything started working.