Wrong TAX calculation per customer group (tier prices)

[marblesystems]

Hi,

I have a weird problem that I can't solve. I have a product with tier prices. And I have different customer groups.

For the first group, the product is 7.40

For the second group the product is 9.58

When I look at the frontend, the price for group 1: is 7.40 and for group 2: 11.59

The 21% VAT is added to group 2, and not to group 1.

I've checked all the configurations, but I can't find it.

Magento version is 2.3. I have spent two days to upgrade to 2.4.2 but that is impossible.

[geissweb]

For the case it is still relevant or unresolved, check that both customer groups have the same tax class.

Go to Customers -> Customer Groups to verify.