CorrectMuzzleVector and Triggers

I'm having some bizarre problems with weapon images. While the player or vehicle holding a weapon is within a trigger, and if that weapon has correctMuzzleVector set to true, something very strange happens -- it's as though the bullets are created within the player, or they start moving into the player.

This stops as soon as the player/vehicle leaves the trigger's volume, or switches to third person. Weapons with correctMuzzleVector set to false don't experience this problem either (though they're unpleasantly imprecise :P).

One of my onFire scripts:

function AirMRImage::onFire(%data, %obj, %slot)
{
   if(%obj.getEnergyLevel() < %data.minEnergy)
      return;

   %obj.setEnergyLevel(%obj.getEnergyLevel() - %data.fireEnergy);
   %data.lightStart = getSimTime();

   if( %obj.isCloaked() )
   {
      if( %obj.getEnergyLevel() > 20 )
      {   
         %obj.setCloaked( false );
         %obj.reCloak = %obj.schedule( 1000, "setCloaked", true ); 
      } 
   }

   %vec = %obj.getMuzzleVector(%slot);
   %x = (getRandom() - 0.5) * 2 * 3.1415926 * %data.projectileSpread;
   %y = (getRandom() - 0.5) * 2 * 3.1415926 * %data.projectileSpread;
   %z = (getRandom() - 0.5) * 2 * 3.1415926 * %data.projectileSpread;
   %mat = MatrixCreateFromEuler(%x @ " " @ %y @ " " @ %z);
   %muzzleVector = MatrixMulVector(%mat, %vec);
   %objectVelocity = %obj.getVelocity();
   %muzzleVelocity = VectorAdd(VectorScale(%muzzleVector, %data.projectile.muzzleVelocity), VectorScale(%objectVelocity, %data.projectile.velInheritFactor));

   %player = %obj.getControllingObject();

   %p = new (%data.projectileType)() {
      dataBlock        = %data.projectile;
      initialVelocity  = %muzzleVelocity;
      initialDirection = %muzzleVector;
      initialPosition  = %obj.getMuzzlePoint(%slot);
      sourceObject     = %player;
      sourceSlot       = %slot;
      origin           = %player;
      client           = %player.client;
   };
   MissionCleanup.add(%p);
   %player.lastProjectile = %p;
   if ( %player.client )
      %player.client.projectile = %p;
}

Nothing I could see there myself that would cause it. Does anyone know what could've caused this, or how to fix it?