I really can’t help you with this, and it’s not really a but. The problem here is that you’re changing the field names. For example, if you had a field named “field_1” and you move it into a group that is named “group_1” the field’s new name is actually “group_1_field_1”. Any renaming of a field will cause the loss of data in that field. The only fix for this would be to go into the database, or to create a query, that renames all of the meta_key values and all of the acf field key references for those fields. The same thing would happen if you had a field with data in it and decided to move that field into a repeater. A group field is basically a repeater field with 1 row.
It might be possible to do this without making db changes. Lets say that you had several fields with names like
- hero_image
- hero_alt
- hero_content
if you made a group named “hero” and then moved the three field into the group and named them
it’s possible that the values would be retained since the meta_keys will actually remain the same.
