Avalara Product Exemption by Category

We are using Avalara for AvaTax sales tax calculations as well as their Exemption Certificate Management system to handle our customer exemptions. We have a large volume of customers that have a sales tax exemption that only applies to certain product categories. For example, if customer buys product A it’s exempt but if they buy product B it’s taxable. Avalara has a feature “Exemptions by product category” and I believe I’ve set that up correctly adding the relevant Avalara tax code to the category then applying that category to the relevant customer exemption, however it doesnt work and charge taxes correctly. It sets the customer as fully exempt regardless of the product type when I test transactions in Acumatica. Does anyone use this feature or can they give me some guidance to a potential workaround?