File Links broken in Aui button

Versions tested

Confluence 6.8.1 and 6.12.1
Content Formatting 6.0.10, 6.2.5 and 6.2.6

Issue

It's not possible to create an Aui Button that URL target is a file link to a network driver.

Steps to Reproduce

1. Create a page
2. Insert a Button Hyperlink Macro from Content Formatting
3. In the URL parameter put as a target the path of a file in network drive for instance "file:///\\DESKTOP-FF153BF\share\test.txt". 

Expected Result

The Button Hyperlink Macro rendering and working.

In this image, you can see the URL parameter without the problem and the button rendered in the preview.

And in this image, you can see the button inside the page example.

After clicking on the button, open the file in the network drive.

Actual Result

When trying to fill the URL parameter with the path of a file in a network drive, doesn't find the file and throws an error on the page.