[8.0.0] Parent row data is reverted when it's changed between row alteration [Urgent]

[AMBudnik]

Description

Parent row data is reverted when it's changed between row alteration.

Steps to reproduce

1. Right-click any parent row and click on Insert Child Row.
2. Enter any data on the same parent row.
3. Again right-click the same parent row and click on Insert Child Row.
4. Parent row data is reverted

Result

Demo

https://jsfiddle.net/b6qy0h79/ 7.0.0 - works well
https://jsfiddle.net/b6qy0h79/2/ 8.0.0 - first broken
https://jsfiddle.net/Lg13seqo/ - 8.3.2 broken
https://jsfiddle.net/Lg13seqo/1/ - 9.0.0 broken

Your environment

• Handsontable version: 8.0.0+
• Browser Name and version: Chrome 91
• Operating System: Windows 10

Inform Zen 26480 p1.1.

[AMBudnik]

Scenario 2 - required to work after fix

• Go to https://jsfiddle.net/4980emLp/
• Right-click the first parent row “Mix” and choose Insert child row from the context menu.
• Change Parent item name from “Mix” to “Mix NEW”.
• Right-click the same parent row “Mix NEW” and choose Insert child row from the context menu.

Result: The parent row changes from “Mix NEW” to “Mix”

[AMBudnik]

Issues to check after the fix

• 'Insert row above' while using nestedRows produces Uncaught error when we use it for a first child [Urgent] #7137
• When we try to 'Insert a child' to a parent that was created via 'Insert row below' on a parent we get an Uncaught error #7138

[wszymanski]

May be related to #6889.

[aninde]

This issue will be fixed by v10 https://jsfiddle.net/sj9cgfah/
Case 2 https://jsfiddle.net/w2arfv6s/

[AMBudnik]

True, works well for my Case 2 as well
https://jsfiddle.net/crvLbdpy/