Let me guess... you are using JBoss 2.x. Right?
JBoss 2.x shipped with commit-option A on by default. Option A assumes that JBoss is the sole user of the database so it can cache anything. In JBoss 3.x the default is Option B which synchronizes with database.
Commit options are set in the jboss.xml file.
Still, why would a access to get Method trigger a ejbStore() ?. Get method triggering an ejbLoad() and set triggering ejbStore() could have made more sense.