Open FDF is broken?

I have Acrobat Reader DC and also Adobe Acrobat Pro DC.

When I try to open an FDF file that contains a reference to a PDF file located on a website both Reader and Acrobat Pro fail.

Steps to reproduce are easy!

1. Open Acrobat Reader DC from the desktop.
2. Go to the File menu and select Open...
3. In the Open dialog, enter a URL for a PDF that is hosted on a website.
4. I used this from the IRS website as an example: https://www.irs.gov/pub/irs-prior/f1040ez--2011.pdf
5. The form displays inside Acrobat reader. Now enter some random data in some of the fields
6. Now, go to the Edit menu / Form Options / Export Data ...
7. Select the save type as Acrobat FDF Files (this should be the default) and save the file on your PC.
8. Close Acrobat and try to open the FDF file in either Acrobat or Reader.

Reader enters in a loop asking over and over in a dialog:

This PDF file is attempting to launch:

file://E:/Users/username/Desktop/f1040ez--2011_data.fdf

Are you sure you want to continue?

You can click Yes until your finger turns blue. It seems it will cycle with the same warning forever.

Acrobat Pro is a little different but still fails:

It will open your default browser and download the fdf you were trying to open. In my case this is chrome and chrome does not support Acrobat plugins anymore.

The Acrobat Pro main window also opens (if it was not open already) but it displays nothing related to the file we intended to open.

Now you may say that it should not open the FDF by it self and that you should first open the PDF and then import the data from the FDF, however this actually works if you use a local PDF file instead of one located on a website. Follow the same steps as above but instead of opening the PDF from the URL, save a copy of the PDF in a local folder first and then do the same.

This time, when you double click the FDF file, it opens the PDF and merges the data into it. NICE!

The only difference I can see (by opening the FDF files and examining its contents) is that the /F reference uses a URL instead of just a local file name.

In short, an FDF with a local file reference to the PDF works while one with a reference to a URL hosted PDF is broken.

Any help or pointers appreciated. I would like to report this as a bug if needed...

thanks