I suspect you'd opened up a virtual root without realising it. If you (as admin) click the final link of a breadcrumb chain it'll do that, i.e. make it the new root via a keep_* parameter.
It may be confusing, so I'll make a note of it in that context menu issue, a context menu option would be a better solution to opening virtual roots.
It may be confusing, so I'll make a note of it in that context menu issue, a context menu option would be a better solution to opening virtual roots.