Tell us what you are trying to do?
I want to change the post type for field group.
But i cant. See the Screenshot.
If i will delete the repeater fields i will loose a lot of customisation.
🙁
As you see the notice on the popup saying that there is a repeatable field group in this custom field group, hence you're not able to change the post type that the field group is assigned to.
It essentially locks the field group to that post type.
You can workaround this by creating a new field group and just reuse you already created custom fields rather than creating new ones.
This is actually expected because it is essentially creating the fields on a different post type.
The data isn't tied to the field settings but the field data is stored per post. What I mean by this is that each post will have its own self contained data. So when the field is added to another post type the field will be empty until you've added data to it.