I have just had a look at this again for you in one of my environments and can confirm that I am indeed able to add “Some text” to one of my files that I drop into the uploader.
My File Object has one property and that’s called “Some Text”, this file object has two relations to my Case object, one to one called initiation file, and a one to many called Submission file, as my case can have many files but will only be initiated with one.
On my Page I have a base object of my case, with a widget group set up, containing 3 widgets.
The first is the DropZone file uploader, under the settings of the uploader I have a relationship using my One to One Initiation File to case, this setting is called “Relationship to file object”
The second widget which uses my One to One relationship and contains only my “SomeText” property,
The third is based on the page object (Case in my instance) and contains a “Submit” element.
When submitting, it is all taken as one record and I do not get the duplicated record that you are getting, I believe the issue you are having is purely relationship based, if you would like to talk this over in a little more detail then I would be happy to set up a Teams meeting to discuss.