When I search for post by Jedi, first listing is "House of Cards - Season 3" thread started by Printer Bandit. Then this thread, then "Selling your stuff to bail out your adult son/daughter from jail?" which was started by you, then ''Should we give this guy a chance? (new hire)" which was started by DS9VOY. So it is a different list from that generated when I ask for only those threads started by you.
If you want to see just the individual posts without the threads, click on your username in a post and then "Find More Posts by JEDI" or change the "Show Results as Threads" to "Show Results as Posts" at the bottom left of the advanced search page.
What I find broken is trying to get posts made during a timeframe. Searching for Jedi posts "a week ago and newer" gets me zero results. If I change it to "a week ago and older" I get the first 500 posts Jedi ever made in 2001. Neither of which is what I'm asking for. Sigh.