Bug: «Update Qty's» click for a credit memo deletes the «Comment Text», «Adjustment Refund», and «Adjustment Fee»

[dmitrii_fediuk]

Before the «Update Qty’s» button is clicked:

After the «Update Qty’s» button is clicked:

[dmitrii_fediuk]

See also:

• How to make a partial refund?
• What is an «Adjustment Refund» for a credit memo?
• What is an «Adjustment Fee» for a credit memo?
• Bug: the setAdjustmentPositive() and setAdjustmentNegative() methods of the \Magento\Sales\Model\Order\Creditmemo class wrongly use the \Magento\Sales\Model\Order's getGrandTotal() method instead of the getBaseGrandTotal() when an adjusment is in percent, so it lead to a wrong calculation result