Update line item in Zoho inventory using Zoho Flow

Hi all,

I have Shopify integrated into Zoho inventory. I sell items mainly with VAT but some are exempt. These exempt sales still need to be reported in the vat declaration hence they have to have a vat code selected. When the orders sync from shopify to zoho the exempt items come with no tax selected. Snip attached

I have been trying to correct this with zoho flow to automatically update the sales orders when this field is blank based on the item's vat rate.

Tried the following flows:

When Sales order created >> Fetch the item searching by item ID and looking for value of Tax name >> Update sales order with the Tax name from Fetch Item

This flow works as I can see it in the log and in addition I wrote a small message (in the flow) under the Customer notes and this was updated but not the tax name for the line item.

Also tried just for the sake of testing:

When Sales order created >> Update sales order with Tax name as 'Tax exempt'.

This did not work either...

Anyone has had any experience with this? Or knows of a better way to create the flows? Am I doing something wrong?