Sorry
I'll try to be clear:
The spec says :
1. include directive should be used to include static content
2. include action should be used to include static/dynamic content.
So we expect static content NOT to be updated when using the include directive. But as you have experienced, content is actually updated, even with the include directive. Why ?
The spec also says about the include directive:
A JSP container can include a mechanism for being notified if an included file changes, so the container can recompile the JSP page. However, the JSP 2.0 specification does not have a way of directing the JSP container that included files have changed.
In clear, it is up to the container to do whatever it wants. There maybe containers that will update pages using the include directive.
The container you are using is acting this way. It will update the content of an included file, even when using the include directive.
BUT:
The spec insists that the directive should be used for static content only, and that you should not rely on the container's behaviour.