The difference between using <jsp:getProperty> and scriptlet <%= %> is that the former gets it's value from the pageContext attributes, while the later from the java variable. In your case,
<jsp:getProperty name="dtBean" property="lineRef" />
will return a null, if pageContext.getAttribute("dtBean") returns null.
If you still have problems, please file a issue report with glassfish, with a simple test case (in war, not ear file). I'll then take a look. Thanks.
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