What is doing the JNDI lookup - another bean or a remote client? I am guessing a remote client because otherwise the bean would be restarted when you bounce GF. Assuming that ...
Do you restart the client after bouncing GF? If so, I have no idea as everything should be "fresh".
If not, my guess is that the remote client has a "dead" connection to GF that isn't being clean up properly and you're actually seeing a TCP/IP timeout. Unfortunately I don't know how to fix this, but you can check it by doing 'netstat -a' and seeing if there are any sockets in TIMEOUT state.
[Message sent by forum member 'matterbury' (matterbury)]
http://forums.java.net/jive/thread.jspa?messageID=353916