Double Fetch in IE

Site-wide Search block submissions cause Active Search to do a double Ajax Fetch of results in Internet Explorer (7 and 8). Results are fetched, displayed briefly, fetched again, and finally displayed. This does not happen when using the Search page search entry textbox, and does not happen at all in Firefox. Tested with fresh install of Drupal 5.20 with no other additions in module, theme, or content other than Javascript tools and had the same results.