[ZScript] NPCs ignoring int Y?

import "std.zh"
//bot = enemy id used for bottle
//botx,boty = initial location of bottle
//dm = next dmap
//sc = next screen
//sfx = boss hit sound
ffc script LV2_Boss_Phase_2
{
    void run(int bot, int botx, int boty, int dm, int sc, int sfx)
    {
        npc bottle = Screen->CreateNPC(bot);
        bottle->X=botx;
        bottle->Y=boty;
	bottle->Extend=1;
        lweapon hammer;
        int currentweaps=Screen->NumLWeapons(); //keeps track of ALL lweapons on the screen (ie bombs, arrows, etc.)
        while(true)
        {
            while(Screen->NumLWeapons()==currentweaps) Waitframe(); //wait until new weapon appears on screen
            if(Screen->NumLWeapons()<currentweaps) currentweaps=Screen->NumLWeapons(); //handles other lweapons that disappear
            else
            {
                hammer=Screen->LoadLWeapon(Screen->NumLWeapons()); //load new lweapon
                currentweaps=Screen->NumLWeapons(); //update tracking variable
                if(hammer->ID==LW_HAMMER) //if lweapon is a hammer
                {
                    Waitframes(15);
                    while(hammer->isValid())
                    {
                        if(Abs(hammer->X-bottle->X)<8 && Abs(hammer->Y-bottle->Y)<8) //if hammer is near enemy
                        {
                            Game->PlaySound(sfx);
			    			Waitframes(60);
			    			Link->PitWarp(dm, sc);
                        }
                        Waitframe();
                    }
                }
            }
        }
    }
}

Ok, so I tried this script in a blank, default quest file, and it worked flawlessly. I took the same exact script, and put it in my main project, and it still works perfectly, however, the script seems to ignore "bottle->Y=boty;". I've gone back and checked the script dozens of times, and I can't find any error. 😞 So is this a bug, or am I missing something really important?

Edit: Here's the quest file, by the way.
Edit 2: Oh yeah, forgot to mention, in that quest file, the script is active only on screens 9-72 and 9-47.
Edit 3: After a bit of testing, it looks like the only NPCs that do this are jumping enemies, like Tektites and Vires.
Edit 4: It seems there are seperate problems for Vires and Tektites. For Tektites, the problem was that I had the "Enemies can fly/jump through Z-axis" Quest Rule checked. I haven't found the problem with Vires yet.