The MgnlGroovyRescueApp depends on the Terminal component which in turn depends on jQuery. In the context of Magnolia, jQuery is provided by Magnolia UI itself. The rescue app, instead, is a standalone, independent Vaadin app which provides terminal with its own jQuery version. Over time this may lead to jQuery version used by the rescue app to diverge from the one used in UI and the rescue app to possibly fail. 

One way to keep this from happening in a production environment could be a UI test to catch issues asap.