That’s often caused by either the lower widget being inside the one above it or you are missing some HTML code; or the widget is too wide for the sidebar width. You can check for mark-up errors by validating the page:
Hi there. Iam having the same problem when I add a new widget to the inner sidebar. It tends to send everything bellow it to the bottom of the page. Yet I have noticed that after one day or two things go back to normal and everything start to show up in the right order. Yet, I Have no Idea of what is causing it. Have noticed that when i Wrap code into div problems diminish though. I just would like to know a way to speed up the recover of the site from 1 or two days to perhaps a few minutes. Does anyone have any Idea?