This is an endless circle from Shopify to Avalara back to Shopify. I’ve have wasted countless hours trying to resolve this and neither party is willing to dive into the actual integration to make it possible to distinguish between normal taxable sales and marketplace facilitator sales.
The work around @gdrinkh2o that I’ve come up with is at the end of every month, I export a sales report from Shopify for the Amazon/TikTok sales channel to Excel. Then I export all the transactions for the same time period from Avalara to Excel. Once I have the two data sources, I can look up on the order number to find the Amazon transactions on the Avalara side. Lastly, I build our a transaction import file that updates the tax amount to $0 for all the Amazon transactions in Avalara. It takes me about 15 minutes for this process. I hope that helps