Rounding issue with the calculation of shipping tax for credit-memo in Magento 2

[blissmagento]

Preconditions and environment

• Magento 2.4.*

Steps to reproduce

1. Create a tax rate in which the Rate Percent is 19%.

2. Create a tax rule that contains this tax rate.

3. Go to Stores > Configuration > Sales > Tax > Tax Classes.
4. Select that tax rule from the dropdown for "Tax Class for Shipping".

5. Go to Stores > Configuration > Sales > Tax > Orders, Invoices, Credit Memos Display Settings.
6. Select Display Shipping Amount As Including Tax.

7. Go to Stores > Configuration > Sales > Delivery Methods > Flat Rate (Any shipping method) > Set its shipping charge as $149.

8. Place an order by selecting that shipping method.
9. Create an invoice for that order and then create a credit memo for it.
10. After the new credit memo is shown set "Qty to Refund" as zero.

11. Refund Shipping (Incl. Tax) set as $75 and then click on Update Totals.
12. See the Grand Total is $75.01 but it should be $75.00

Expected result

The expected result in a Grand Total should be $75.00.

Actual result

The actual result in Grand Total is $75.01.

Additional information

This issue is also produced when the value of Refund Shipping (Incl. Tax) is 76.
Also, when the value of Refund Shipping (Incl. Tax) is 74 & 73 but in that value the Grand Total value is decreased by one cent. For 74 Refund Shipping, the value of the Grand Total is 73.99 and for 73 it's 72.99.

Release note

No response

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

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[m2-assistant]

Hi @engcom-Bravo. Thank you for working on this issue.
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[blissmagento]

@engcom-Bravo This issue can be reproduced in Magento version 2.4.7-p4 and demands prompt resolution.

[engcom-Bravo]

Hi @blissmagento,

Thanks for your reporting and collaboration.

We have tried to reproduce the issue in Latest 2.4-develop instance and the issue is reproducible.Kindly refer the screenshots.

The actual result in Grand Total is $75.01.

Hence Confirming the issue.

Thanks.

[github-jira-sync-bot]

✅ Jira issue https://jira.corp.adobe.com/browse/AC-14012 is successfully created for this GitHub issue.

[m2-assistant]

✅ Confirmed by @engcom-Bravo. Thank you for verifying the issue.
Issue Available: @engcom-Bravo, You will be automatically unassigned. Contributors/Maintainers can claim this issue to continue. To reclaim and continue work, reassign the ticket to yourself.