Hi! If the player is in a prone position, and he want use his launcher, then the player's character automatically rises to the full height and begins the animation of taking the launcher from his back. At this moment, it is impossible to use a crouch! Player can press the Crouch-button even 10 times, but it will not work, until the the switching animation is not be finished! Just imagine that at that moment the enemy shoots at you.
There are two ways to solve this problem:
1. From the prone position, the player will automatically go not a full height stance, but to the crouch position
2. During the take of weapons from the back, the player's character will be able to switch from fully erected/crouch and vice versa. This already works for any weapon (except Launchers)