Submitting a new bug based on one I recently reopened as it pertains to 1.2 and 2.0 impls as well:
Referer bug: https://issues.apache.org/jira/browse/MYFACES-702
Problem reported in the above bug is related to the component's id being prefixed with the portletNamespace which is caused by calling encodeNamespace. Why is this api called in generating the component id. encodeNamespace was added to external context by and large for the portlet environment to allow it to prefix client ids to be unique on the page they are being incorporated into. Is there a reason for needing this when generating the component id? FYI ... Mojarra doesn't make this call from createUniqureId.
Hopefully, this is something that can be fixed by just removing the call ....