It’s a breadcrumbs failure. Once you’ve navigated to it, any pages you click to (for example ‘You may also like’, any of your recently viewed items on the right, or even _SEARCHING_) will end up thinking they are under the breadcrumbs for the segment that you initially clicked down into.
I see this most often in the ‘fast grab’ section, because it’s a particularly interesting section to check out, to see the stability of the site. (There are three distinct prices for most of the items, that show up under certain different circumstances.) If I navigate to any other items from there, the site thinks I’m still in the ‘Fastgrab section’, as per the screen snipped attached below.
I have guesses about why it’s behaving that way, but they’re wild speculation about how Magento constructs categories. It’s mainly just a display aberration, however, so I wouldn’t expect it fixed this side of the heat death of the universe. It is consistently happening, at least, which might mean it’s easier for them to debug.