Yes we have seen this issue mainly in IE not Firefox. The browser cache would need to be cleared for it to pick up the new swf file.
We ended up adding in a version check to be sure the user is running the latest swf Also see: http://livedocs.adobe.com/flex/201/html/wwhelp/wwhimpl/common/html/wwhel p.htm?context=LiveDocs_Book_Parts&file=performance_118_13.html
