Steps to reproduce the issue

1. Navigate to Content → Articles → Options
2. Under the Articles tab, set Show Intro Text to Hide
3. Under the Integration tab, set Include in Feed to Full Text
4. Click Save & Close
5. Create at least two articles with the following content:
   • Intro text: "AA1" (or "AA2")
   • Insert a Read More break (CMS Content → Read More)
   • Full text: "BB1" (or "BB2")
6. Mark these articles as Featured (click the star icon in the Articles list)
7. Create a Featured Articles menu item (e.g., alias: "featured-feed-test")
8. On the frontend, access the RSS feed using the URL:
   • http://localhost/featured-feed-test?format=feed&type=rss
   • Or directly: http://localhost/index.php?option=com_content&view=featured&format=feed&type=rss

Version

5.4

Expected result

The feed should show only the content after the Read More break ("BB1", "BB2") because Show Intro Text = Hide.

<description><![CDATA[<div class="feed-description"><p>BB1</p></div>]]></description>

Actual result

The feed shows both intro text and full text concatenated ("AA1" + "BB1", "AA2" + "BB2").

<description><![CDATA[<div class="feed-description"><p>AA1</p>

<p>BB1</p></div>]]></description>

System Information

• Joomla 5.4
• PHP 8.5

Additional Comments

This is the same issue at #41445, but for the Feed for Featured Articles.
I made a fix for that issue; this one needs the same fix for Featured Articles.