Pages inaccessible with uniquify enabled in a specific setup

[vifon]

Steps to reproduce

1. Enable uniquify (a package which automatically renames the buffer names to make them unique in a sensible way).
2. (setq uniquify-buffer-name-style 'forward)
3. Open ~/dir1/example-file and ~/dir2/example-file.
4. Enable impatient-mode in ~/dir1/example-file.
5. Try to access it in a web browser.

What happens

The requested URL is forbidden.

error: Buffer dir1 is private or doesn't exist.

What was expected

The file's contents should be displayed.