I could replicate this Successfully ✅
This is what I found:

<item>
			<title>Test RSS Article</title>
			<link>http://localhost/category-blog-menu-for-article-setting/test-rss-article</link>
			<guid isPermaLink="true">http://localhost/category-blog-menu-for-article-setting/test-rss-article</guid>
			<description><![CDATA[<p>AA</p>

<p>BB</p>]]></description>
			<category>Uncategorised</category>
			<pubDate>Sun, 10 May 2026 20:02:32 +0000</pubDate>
		</item>

I personally don't know yet if this is the correct way (otherwise won't be applicable or is meaningless) or if it is a bug.
Maybe someone with a better understanding can tell us @Hackwar.
I might work on this though.

Testing performed on Joomla 5.4

Issue: RSS Feed ignores "Show Intro Text = Hide" setting when "Include in Feed = Full Text" is selected

Steps performed to replicate:

1. Navigated 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. Clicked Save & Close
5. Created a new article with:
   • Title: "Test RSS Article"
   • In the content area, typed "AA"
   • Clicked the Read More toggle (CMS Content → Read More)
   • After the read more break, typed "BB"
   • Saved the article
6. On the frontend, accessed the RSS feed using the URL:
   http://localhost/category-blog-menu-for-article-setting?format=feed&type=rss

Result observed in the feed:

<item>
			<title>Test RSS Article</title>
			<link>http://localhost/category-blog-menu-for-article-setting/test-rss-article</link>
			<guid isPermaLink="true">http://localhost/category-blog-menu-for-article-setting/test-rss-article</guid>
			<description><![CDATA[<p>AA</p>

<p>BB</p>]]></description>
			<category>Uncategorised</category>
			<pubDate>Sun, 10 May 2026 20:02:32 +0000</pubDate>
		</item>

Expected result (with Show Intro Text = Hide):
Only BB should appear in the feed description

Actual result (bug):
Both AA and BB appear in the feed description

Comparison:

• HTML view (full article): Only BB appears ✅ (correct behavior)
• RSS Feed: AA + BB appear ❌ (bug — Intro Text should be hidden)

Conclusion:
The RSS feed generation code ignores the Show Intro Text = Hide setting. When "Include in Feed = Full Text" is selected, it should output only the content after the Read More break when Show Intro Text is set to Hide, but instead it outputs both intro text and full text concatenated.

System information:

• Joomla 5.4
• Feed URL tested: http://localhost/category-blog-menu-for-article-setting?format=feed&type=rss

Nevermind, I have fixed this.

@vdneut, could you please test #47756?
Thanks in advance.