Went on a trip to FL going to Vero than Ft. Myers (About 1,000 miles) and 3-4 times I had mashed the go peddle to pass someone and had to immediately let up for one reason or another and each time the tranny down shifted but did not go back into 6th, but stayed in 3rd or 4th and I had to play around with the gas peddle to finally get it back into 6th.
The last time it happened, tranny stayed in 3rd for a couple of minutes.

Does this sound like a tranny issue or did I confuse the TCU and it did not know how to react?

Car is a 2007