Control Devices & Wheel Issues

[Krazy]

Hey,
After a long time trying to fix that problem (and even taking a break from RNR because of this) i come back here to see if someone can help me.
the problem is that neutral gear is not working (it's suppose to go to "neutral" if i don't select any speed but in my case, it's staying in the last gear engaged (so if i'm using 2nd , i stop the truck, put the gearbox on neutral, it's staying in the 2nd)

Is it normal? if not, somebody with a g27 can explain how they avoid this problem?
Thanks in advance to anybody