To fix Bug #1162790 (Failure during reconnect phase for the client in multithread environments) the ejb-client need to be upgraded to include EJBCLIENT-121 which is included in 1.0.28 This is the 6.4.0 upgrade bugzilla.
MEAD build: https://brewweb.devel.redhat.com/buildinfo?buildID=408612 RPM6 wrapper: https://brewweb.devel.redhat.com/buildinfo?buildID=408619 RPM5 wrapper: https://brewweb.devel.redhat.com/buildinfo?buildID=408622 RPM7 wrapper: https://brewweb.devel.redhat.com/buildinfo?buildID=408634 PR: https://github.com/jbossas/jboss-eap/pull/2210
Verified in EAP 6.4.0.ER1.