Discount code disappears at the time of placing the order

[dmytrokravch]

Current behavior

After registering on the /checkout page at the time of placing the order, discount code disappears

Expected behavior

Steps to reproduce the issue

1 Create an account on Personal Details step
2 Place the order

Repository

Can you handle fixing this bug by yourself?

• YES
• NO

Which Release Cycle state this refers to? Info for developer.

Pick one option.

• This is a bug report for test version on https://test.storefrontcloud.io - In this case Developer should create branch from develop branch and create Pull Request 2. Feature / Improvement back to develop.
• [x ] This is a bug report for current Release Candidate version on https://next.storefrontcloud.io - In this case Developer should create branch from release branch and create Pull Request 3. Stabilisation fix back to release.
• This is a bug report for current Stable version on https://demo.storefrontcloud.io and should be placed in next stable version hotfix - In this case Developer should create branch from hotfix or master branch and create Pull Request 4. Hotfix back to hotfix.

Environment details

Browser: Google Chrome Version 81.0.4044.17
OS: Win 10
Node: 10.15.2
Code Version: 1.11.1

Additional information

[pkarw]

This is because the shopping cart is being resynced between guest and registered users cart . We need to improve the “cart/merge” method to synchronize the shopping cart discount code as well in order to fix this edge case