Hi @soojooko
Thanks for the bug report and very clear explanation!
The issue here is due to a ‘some what’ miss-use of the conditional logic functionality.
If a field is hidden by conditional logic, ACF will not save it’s value when the form is submitted. This is why the hidden fields do not update correctly, and why a new field simply overrides existing data.
I think you may be interested in the flexible content field. You can use it in the same way as a repeater, however, each ‘layout’ is collapsible. This means you can minimize the interface and toggle open/close the WYSIWYG editors without using conditional logic.
Thanks
E
