The root context, normally seen as biz-layer context, is normally defined as "applicationContext.xml" and loaded by ContextLoaderListener.
The other context, the web-layer one is normally defined as "mvc-servlet.xml" and loaded by DispatcherServlet.
The web-layer context will inherit beans from the root one, Except some processors such as PropertyConfigurator. As a result, you should define two PropertyConfigurators. One for the biz layer, the other for the web layer. See https://stackoverflow.com/questions/11890544/spring-value-annotation-in-controller-class-not-evaluating-to-value-inside-pro
You may argue that your system has only one PropertyConfigurator and things work fine. In this case, it’s highly possible your web-layer context is scanning biz-layer classes, in addition to the web-layer classes. As a result, your biz-layer spring beans have been loaded twice, one by the ContextLoaderListener, the other by DispatcherServlet.