Error 404 when executing LCM Export from Groovy BR using Connection via REST API

Summary

Attempting to trigger an LCM Export via REST API call in a Groovy BR results in 404 error

Content

Tried this with named connections as well as hard-coded URL in the Business Rule, with the same result.

Trying to trigger an LCM Export from a Groovy Business Rule, utilizing the Connection to call a REST API. While "simple" calls work, trying to get it to work with calls that require queries, results in 404 error. For example, 

https://<inst-url>.pbcs.us2.oraclecloud.com/interop/rest/11.1.2.3.600/applicationsnapshots/<snapshot-name&gt;  works

but,

https://<inst-url>.pbcs.us2.oraclecloud.com/interop/rest/11.1.2.3.600/applicationsnapshots/<snapshot-name>/migration?q={"type":"export"}