Wow...I'm so glad I found this forum. I have a 2005 Jeep Grand Cherokee that the same thing happened to last spring. We had it all hooked up for towing behind the motorhome ready for 1200 miles trip to Wisconsin when wouldn't go into neutral. And yes, the Jeep had the N23 software fix done previously at the dealer. Anyway, unhooked the Jeep, drove everything to the dealer and waited for them to open. Got in pretty quickly...they did a flash module thing and all OK. Dealer said something about actuator and $700-800 dollars and I said maybe later as we needed to get on the road. Drove to WI and then back with no issues, but then same thing happened on next short trip to beach. I drove the Jeep home separately as wouldn't go into neutral, but that's a short 1.5 hr trip. Haven't called the dealer yet to tell them about this forum, but will do soon as have another beach trip planned.
It's a shame that Jeep hasn't stepped up to the plate here and been helpful to the owners. Satisfied & happy customers are repeat customers!!! Jeep needs to go back to school on this one.