See description of linked ISPN-4501
I tried to reproduce it on my local machine (Ubuntu) and on RHEL 5 x86_64, with both OpenJDK 1.7 and IBM JDK 1.7 but without success -> can't reproduce it. I suppose this is some environmental issue in Jenkins.
I tried with ER7 and also latest Infinispan snapshot and I can't reproduce it. I'm closing this BZ. Please let me know if the failure appears again.