This is NOT a bug, I have tested it and it works fine, you HAVE to pick your settings for the %, then DELETE and rebuild your index, if you have alot of posts then it might take a while.
but it works fine, you probably aren't reindexing it after changing it.
HB wrote:I kept the search index from 3.0.2, but would like to rebuild the tables after adding ignored words to the install. Problem is, the search "in progress" window sometimes times out, forcing me to start from the very beginning. The 2.0.x mod for rebuilding the index was smart enough to continue from where it left off, why not the official version?
try using another browser, or try when the server is less stressed.