After installing release com_easystore_v1.8.0:
In Easystore settings, it states that VAT is included in the product price, yet for one item, charging VAT is not enabled!!
After installing Easystore release com_easystore_v1.8.0, charging VAT was suddenly enabled for every item, causing every product in the webshop to show up incorrectly!!
The solution was to disable charging VAT for 200 items!
I cannot understand why this is not noticed in your tests!!