Yeap! It is not a problem on the mockup page since the mockup is a mockup :)
In our uPortal instance, the carousel content links out to external websites/applications. We accomplish this by setting the alternativeMaximizedLink portlet-preference when creating the portlet definitions.
The links open in a new tab/window because that is the behaviour we want when we link to external websites/applications.
With that, the use case of carousel slides linking to content within uPortal has not been encountered ... until now.