As Rampant said, there's two types of Meth listed in the spawner. I found that in my experience, the one you're looking for is the one on page 2, (not the default page). IIRC, it's the page that doesn't have the VR headset on it. If it's not that, then use the other one.
My suggestion for this is to rename this loot as Meth -Cook Off so people know what one to use. I personally ran into this same issue and found this thread and tried what Rampant said so I think this would prevent the issue altogether. Also, maybe switching the pages that both meth bags are on, since people play Cook Off to level up and is the best way to do it, therefore more use than the other one?