@Ch.Cole I use legacy one, but I tried the modern method and I had the same issue. I think the problem is that the plane 3D cockpit lever stops correctly to prevent to enter accidentally in beta range, but you may continue moving your joystick throttle lever... so when you click (execute) the lift command, the plane lever goes to where your joystick lever is... so if you accidentally moved it to the lower position then plane goes to full reverse.
In other words, prevents accidentally beta ranges but then you have to pay attention to your joystick lever position or it goes full reverse... so one way or the other the "accidentally" option is there... honestly I don't see the advantage of this method unless you have a joystick lever with a physical lever stop, so then you don't need this method either.
Of course, maybe I was using it a wrong way too.... so I decided to go old school legacy.