TYPO3 Core

When I set an attribute rel="nofollow" to the href tag :

<a href="http://typo3.org/" rel="nofollow" target="_blank">Best site http://typo3.org/</a>

the result in frontend is duplicated href tag, and only one of them have set attributes:

<a href="http://typo3.org/" rel="nofollow" target="_blank">Best site</a>
<a href="http://typo3.org/">http://typo3.org/</a>

This situation occurs only when in the linked text is placed the url.

I have looked to database and the content is stored correctly here.