In our product we have found strange behavior of JpaMessageIdRepository when change version 2.9.2 to 2.12.3.
The reason for this was that EntityManager assigned in the constructor org.apache.camel.processor.idempotent.jpa.JpaMessageIdRepository, but
EntityManager not required to be thread safe.
http://download.oracle.com/otn-pub/jcp/persistence-2.0-fr-oth-JSpec/persistence-2_0-final-spec.pdf page 286.
I think need assign the EntityManager in each method separately.