data missing, but not the record...weird

Tomcat/Struts2/JPA2(EclipseLink)/MySql

I have several differen开发者_StackOverflow中文版t entities that are exhibiting an intermittent problem and I am puzzled.

• Most of the time EntityX shows up everywhere it is supposed (edit form, lists of EntityX, etc.)
• Every so often, an instance of EntityX (or Y or Z) will be blank. Whether retrieved by itself (edit form) or in a list of EntityXs.
• By blank, I mean the record shows up but all fields are blank/null. A better example: in a list of EntityXs (in a web page), there is actually a blank row where this instance of EntityX is, but no actual field data.
• I go directly to DB and all is well, all data is there.

At a loss, I restarted Tomcat and that "fixed" the problem temporarily, but it continues to surface. Also noticed that once all the Tomcat sessions expire after users go home, problem goes away without restart. Tomcat could be the issue I know, but can't imagine what. JPA was my first guess.

Any thoughts would be helpful.

Thanks.