The vape cartridge industry is going to take a big hit, especially the black market. I hope whoever, whatever is causing this gets solved though.
The three possible culprits in my mind are adulterants(cuts, fake products, etc), pesticides, or bad cartridges. Could even be an unintended contaminant introduced from using containers or utensils during manufacturing of any of the items. GMP exists because of such unintended contaminations.