CXF-6665 is found as a regression in Apache CXF 2.7.18, but it won't be fixed in the upstream because 2.7.x is EOLed. A customer hit the same issue and it's better if we backport the fix to our version. EAP 6.4.11 (Apache CXF 2.7.18.SP3-redhat-1) is the same. While EAP 7 is free from the issue because the major version of CXF has changed.
PR: https://github.com/jboss/cxf/pull/10
Verified with EAP 6.4.13.CP.CR2.
Released with EAP 6.4.13 on Feb 02 2017.