Inline Editing Multiline Text field only works for most recent items now

1. Check the field settings: Open the SharePoint list and click Settings > List Settings.
Locate the multi-line text field and click on the field name.
Ensure that the “Allow inline editing” option is enabled. 
2. Check the list view: Open the SharePoint list and click on “View” > “Modify View”.
Ensure that the Allow inline editing option is enabled. 3. Check Browser Compatibility.
3. Check Browser Compatibility: Ensure that the browser you are using is compatible with SharePoint (e.g. latest version of Microsoft Edge, Chrome, Firefox, etc.).
Clear your browser cache and cookies and try again. 
4. Check permission settings: Make sure you have editing permissions for the old item.
Contact the SharePoint administrator to check the permission settings.
5. Check content type: Open the SharePoint list and click Settings > List Settings.
Check the content type settings and make sure inline editing is enabled for multi-line text fields in all content types.
6. Using a PowerShell script: If the issue only affects older items, you can try updating the field settings in bulk using a PowerShell script. Example:
powershell
$web = Get-SPWeb “https://yoursharepointsite”
$list = $web.Lists[“YourListName”]
$field = $list.Fields[“YourFieldName”]
$field.AllowInlineEdit = $true
$field.Update()
7. Contact Microsoft Support: If none of the above methods work, it is recommended to contact the Microsoft support team with detailed error messages and screenshots for further assistance.