There is a folder in the HPTuners editor called Transmission Diagnostics where you can find a few parameters that restrict gear command. Our STOCK numbers are set at 5500 rpm and 62 mph. The rpm and mph must be UNDER these two parameters to enable gear control. MY current modified file on the car is set at 6200 rpm and 188 mph. Looking at my scan, the mph was at 145 mph, below the 188 requirement, and rpm was at 6050 which is under the 6200 rpm requirement which will allow gear command. This explains not only how it is possible to occur but why guys with stock trans tunes or just ratio changes cannot command a downshift when going over a certain speed.
The TC used in my transmission package is not designed to be locked during WOT. The TC was locked during the dyno testing and could have been damaged. Debris could of then of been throw back into the transmission.