This used to be a periodic problem in AH2 with the x52. Back then I deleted all the jsm files and started over as one fix.
At least once I did the copy of Mode1 to Mode2 option and forgot to setup Mode2. It looked like I was not getting the auto switch. There is a Hide Msg check box, if that is checked, you cannot verify from the text bar with a system message that Mode2 was auto selected when you spawn out in a vehicle. You need that message to verify Mode2 is even happening automatically for GVs. Another thing to check is open the jsm file in notepad and see if the key presses you are using for GV's are being saved into the line2 for each button. Many players forget to hit the OK button after they setup a Mode in the controller application window. I've done that one at least once in all these years.
All of this has to be eliminated before a bug problem can be pointed to. And then running a new complete re-install never hurt. That was another way in AH2 some players fixed this issue. I did once.