Yeah glass path means nothing if the coil is still metal. The volcano and some of the other more high end devices use an oven, so the only thing coming into contact with your material is hot air.
The weed carts are just so suspect nowadays. It’s incredibly hard to know legit vs. counterfeit, and with little to no federal regulation, who knows what chemicals have been added.
That’s why so many of those studies are meaningless. They don’t necessarily represent the way the population vapes, and what exactly they're vaping. Until a comprehensive study is conducted of a wide range of materials, and devices… they shouldn’t present their findings as fact.