I have the problem that when I use the call for tender function in purchasing, the tax does not carry over from the original RFQ. 

In the purchase app, create an RFQ, add products then click Alternatives tab and Create Alternative. I choose an alternative supplier and tick the "Copy Products" box. The problem is the tax on the purchase order lines is empty (not populated). 

I have checked the vendor details, they don't have a fiscal position set so there should be no deviation from standard tax. I have checked the product and on the purchase tab the Vendor Taxes are set at Standard rate purchases (20%). On the original RFQ this populates fine.

This issue happens regardless of the alternative vendor chosen.

Am I missing a setting? is there a solution?