If a player is in the prone stance with an under-slung grenade launcher (UGL) selected and "deployed" (default "c" key) and increases the UGL's sight zeroing to a high range (especially 400m), then the player's body model will appear to sink into the ground significantly.
- Legacy ID
I created a ticket and wasn't aware, that your ticket is far related to mine: #0023767
I hope, the developers will find a solution, because at the moment, you are not able to shoot your under barrel grenade launcher, after you deployed your weapon.
I think, an extra animation is needed.