If you click on the title of a folder which has items inside it, then click on the top-level folder name in the Breadcrumbs on the resulting page, you return to the top-level folder, but the folder that you just returned from is shown expanded. However the icon next to it is shown as a + rather than -. Its state is therefore inconsistent.
When you return to the top-level collection, it should be the same as clicking on the tool reset button (I think), i.e. the folder should be shown collapsed.