User blog comment:LazyTiger/Weapon disappeared after patching and installing DLC3/@comment-1808057-20100311114642

So it turns out "Trauma" is a Grenade Launcher title, just like "Fat" or "Blitz". So the Rocket Launcher is modded. Long story short, you had modded weapons, the patch did what it was supposed to, and now you don't have modded weapons any longer.