Server - Edit or add an item erase it

How to reproduce

• Create any checklist from configuration panel
• Create an issue including the checklist created
• Add an item 
• Modify this item or add another item

Expected result

• Edition mode is activated with data of the item displayed 
• Both items are created

Actual result

• Data in the edition mode is erased
• Data from the first item is erased

Affected version of Jira: 8.20, 8.21