Steps to reproduce:

1. Start stock emacs 25.1:
$ emacs -Q test.org

2. Write a headline
* Test

3. Issue C-c C-c and the headline to add a tag
* Test           :test:

4. Modify the headline to include a link.
* Test [[http://test][test]]          :test:

5. Everything appears to be rendered correctly, but when viewing the
source, it really looks like:
[[http://test][te]]st

6. To make it render wrong and become very obvious, change the link
description to have multiple words.