Sounds like you are having the same exact problem as me. Did not notice a problem until I passed the 4,000 mile mark. I have not experienced this with any of my previous vehicles, although this is the first one I have had with a 6 speed trans. I have tried both harder and softer acceleration, and it still seems to be present no matter what RPM it shifts into 5th at. Also, 5th seems to be the only one with the issue, all the other gears shift without such a large jump in RPMs. It is a pretty noticable jump in RPM though, especially when you are driving with the windows down and can really hear the engine rev when it shifts. Luckily, I am so pleased with the vehicle overall that it's not going to kill me to have to live with it- thank God for the famous Ford 2 year lease program. Hopefully the issue will be corrected when I'm ready for my 2009 Edge.