Screwey Trans Malfunction

Last night on my 05 LE I was driving home in bumper to bumper traffic. For some reason my Nav system wasn't working, it only showed radio functions and AC etc. I had this happen one other time when I had my 04 LE, and I just turned the mada off and restarted and it was fine. Last night since I was in traffic, I put the mada in neutral (was probably rolling about 25 mph or so), turned off the key, waited a second, and restarted the vehicle, then put it in drive. Vehicle was in 2wd at the time. A few minutes later I noticed that when I went to take off the veihicle was really "dragging", and straining to pick up RPM's, I thought the tranny was slipping. It was down pouring and freezing rain in the middle of no where, and I had just worked 17 hours on an emergency for a client, so I really didnt want to get stuck so I kept driving. Turns out the mada wasn't shifting out of third gear. 75MPH was around 3500 RPM (approx), and I couldn't get it to downshift or up shift from this point. I drove it all the way to within a few miles of my house, stopped the car, restarted it and all is well again. Anyone have any idea why shutting the car off in neutral while rolling could have caused this?? Do you think it just tripped up the computer?? I did not get a AT Warning light, and I did notice that the tranny temp would increase when I was going slower (as expected). What do you guys think?