Recently, we encountered an interesting and quite unexpected issue while working on a publishing site based on SharePoint 2013. Let me share some details on that particular scenario and a simple workaround in case you come to struggle with the same problem.
A client of ours has a large number of pictures that they use when authoring content for a publishing site. They store the images in the Site Collection Images library. To make it easier to classify the images and simplify the work of content authors, they added a Managed Metadata field named Category to the library. This works pretty well since a new feature in SharePoint 2013 now allows to conveniently sort and filter by taxonomy fields in the list view: