The "Thanks for your edit!" banner appears to be stuck in these posts:
You can see the banner even if you are not logged in.
Fortunately for us, these were the only 3 posts on Stack Overflow for which this banner was stuck. And all three had suggested edits submitted (and rejected) near the end of January 2011. This was around the time that we were first rolling out the suggested edits feature, so this bug was likely introduced and fixed a long time ago.