Currently the autoHide option for Tooltips always hides when the mouse leaves the target element.  This makes sense for showOn values "mouseenter" and "click", but does not make sense for showOn "focus". In the latter case the mouse might not even be over the target when the tooltip is shown, so autoHide is not useful (and indeed you get weird behaviour like multiple tips appearing).  It seems the obvious behaviour for autoHide in this case is to hide on blur.  See also the forum thread:

http://www.telerik.com/forums/tooltip-doesn't-hide-when-element-lost-focus-when-set-to-showon-focus