iFrame removes content if first item in post

Development
2

I’m unable to reproduce. Is there some specificity about the text? :thinking:

The image shows a computer screen with a web interface on the left side that has an editor with text and an embedded iframe code snippet, and on the right side there is a preview of a CodePen project titled "Smooth Flexbox Navigation" with options to run the code and view it in HTML, CSS, and JS tabs. (Captioned by AI)
The image shows a computer screen with a web interface on the left side that has an editor with text and an embedded iframe code snippet, and on the right side there is a preview of a CodePen project titled "Smooth Flexbox Navigation" with options to run the code and view it in HTML, CSS, and JS tabs. (Captioned by AI)975×267 15.7 KB