In upcoming API releases Shopify is deprecating the taxCode field on the productVariant object because of the Avalara App deprecation.
We are on the new setup with Avalara and using the metafields so there is no issue there for us but I do see that in the current Shopify-Netsuite integration app that the queries/mutations for products still have the taxCode field listed.
Wanted to confirm that will be removed whenever you next update the API versions?