They are applying the tax to goods based on where they are sold and not what they are. Resistance wire, loose batteries, cotton, nicotine, o-rings, screws, VG, and even water are taxable OTP if sold in a "vape shop" but not if they are sold at another retailer. Lowes also does not need an OTP retail license to sell them, but a vape shop does. Walgreen's and the like are in an even stranger spot, they have an OTP retail license, sell vapor products that are taxed, but sell some of the same items as untaxed non-tobacco products that "vape shops" are required to tax. A suit based on this violation has already been filed by a PA based company that is both a wholesale distributor and retailer.
There are other issues, but not necessarily illegal. These issues are good ammo for defense if the DoR takes action against an individual, but not something that can get the law struck down directly. The DoR is not implementing the law that was passed. They have messaged the implementation to what they wanted it to be, not what is written into law. The law offers no exemption to pharmaceuticals or plant medicine, but DoR is giving them a pass without going to the effort of updating the legislation. Out-of-state retailers are being told they need to have an OTP retail license and need to remit both OTP excise and use tax directly to the state of PA. They don't, but DoR can lie and lead them to believe they do. The law actually places the responsibly on the in state consumer. The DoR is telling out-of-state retailers that are not wholesalers, they are to apply the OTP tax to the retail price. The law as passed specifically states the tax is applied to the wholesale cost.