Unable to manipulate serverclass whitelist via REST

We're trying to script some whitelisting of hosts in serverclasses, hit a snag. We create a test serverclass named 'posttest' with one app and nothing in the whitelist. When we try to add a host: curl -x '' -k -u admin:xxxxxxx https://splunk-c-ds.local:8089/services/deployment/server/serverclasses/posttest -d whitelist.0=posted_host we get this response In handler 'serverclasses': bundle=serverclass stanza=serverClass:posttest The sourceApp=system doesn't equal callerApp=search This appears to be the same issue seen by a212830 seen down in the notes for [https://answers.splunk.com/answers/307335/why-am-i-getting-error-cannot-perform-action-post.html][1], no there is no solution posted there. We're running 6.3.0.1. [1]: https://answers.splunk.com/answers/307335/why-am-i-getting-error-cannot-perform-action-post.html