Couch

Working fix for this issue. Decompiled using MCP 9.40-Pre1 in the class net.minecraft.pathfinding (Note that this fix isnt perfect!)

public Vec3d getCurrentPos()
    {
    	System.out.println("currentPathIndex: " + this.currentPathIndex);
        //Start of the fix
    	PathPoint pathpoint = null;
    	try {
    		pathpoint = this.points[this.currentPathIndex];
    	} catch (Exception e) {
    		pathpoint = new PathPoint(0, 0, 0);		
    	}
        //end of the fix
        return new Vec3d((double)pathpoint.xCoord, (double)pathpoint.yCoord, (double)pathpoint.zCoord);
    }

Confirmed for 17w18a