In the first image you can notice that there's an artillery in a darkened tile near Groningen but you can't see it on the map. If select another unit you can gain control over the artillery again only if you use the Military Overview. The same happens in the strategic view (second image).
EDIT: I haven't realized that this bug comes from vanilla: http://forums.civfanatics.com/showthread.php?t=396035
EDIT: Removed the savegame because the bug is now fixed.
EDIT: I haven't realized that this bug comes from vanilla: http://forums.civfanatics.com/showthread.php?t=396035
EDIT: Removed the savegame because the bug is now fixed.