Yes my animations are set as additive animation in the state machine, it looks like that the different state in the state machine cannot play the animation anymore. If i switch my boolean on and off in the preview window I can see the transition arrows in the state machine changing color but it does not enter the state and does not play the animation in 4.14.
I have the same setup for an helicopter and it is still working fine in 4.14, therefore I think the problem comes from the fact that i am using a vehicleAnimation instance in order to use the WheelHandler.
If i change the animation class to animationClass and not vehicleAnimation class the state machine works fine but i cannot use the wheelHandler anymore.