Credit Memo - Wrong tax calculation!

[andidhouse]

Preconditions

1. Magento 2.1.7 via download
2. Nginx, php7, varnish, redis

Steps to reproduce

1. Create tax class for product with 19%
2. Create Shipping tax class with 19%
3. Order a product with shipping costs
4. create a credit memo of the product cost (with the shipping costs)

Expected result

1. The credit memo (for the article only) includes just the tax for the product - not the shipping tax of course

Actual result

1. The credit memo includes also the shipping tax which is totally wrong as the shipping costs where not refunded. Screens attached.

I think there are 10-20 tickets reported nearly close to this one - i am not shure why the magento team does not check all aspects of the credit memo to get rid of all bugs. Also this is worst case with payment methods like PayPal which refund the credit memo amount automatically - so this leads to serious problems in the accounting.

There is also a massive bug in the credit memo creation. The total amount does not change in the credit memo backend if you change the Adjustment Fee/ Refund at all - Using Safari for Mac. Could you pls also check this!

[andidhouse]

This only happens sometimes - some refunds are ok - some have a calculation error.

I am also questioning why there are two ways to refund an order:

1. Create a credit memo over the order page directly
2. Create a credit memo over the invoice page

We realized this bugs only appeares on the credit creation when we do a credit memo over the invoice (which needs to be done to create an online refund).

Not shure why there are two ways?

[magento-engcom-team]

@andidhouse, thank you for your report.
We've created internal ticket(s) MAGETWO-82400 to track progress on the issue.