Fix "Add new item" in list where user has Read only on list level but "Add item" permission under folder.

Fix "Add new item" in list where user has Read only on list level but "Add item" permission under a folder. Now it becomes an authentication error.

(SharePoint Online and Nintex Automated Could.)
If we use regular SharePoint form, there is no issue. But by just publishing a Nintex form result in authentication error when try to add a new item.
A support case has already been raised and the findings where, Microsoft has made this by design. Any SPFx forms will go through List then Item permission. So, you cannot use Nintex forms if you have only read on a list and have "add item" permission on folder. That will result in permission denied.