bootstrap-wysihtml5 changing iframe src

Question

I want to use Youtube abd Vimeo iframe code in wysihtml5 editor. I have used

('#answer').wysihtml5();

and

$('#answer').wysihtml5({
      toolbar: {
        "font-styles": true, // Font styling, e.g. h1, h2, etc.
        "emphasis": true, // Italics, bold, etc.
        "lists": true, // (Un)ordered lists, e.g. Bullets, Numbers.
        "html": true, // Button which allows you to edit the generated HTML.
        "link": true, // Button to insert a link.
        "image": true, // Button to insert an image.
        "color": false, // Button to change color of font
        "blockquote": true, // Blockquote
        "size": "sm" // options are xs, sm, lg
      }
    });

Following Iframe code I am using

<iframe width="560" height="315" src="https://www.youtube.com/embed/zJZKWF7YBas" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>

In database I see it like following

<p>&lt;iframe width="560" height="315" src="<a href="https://www.youtube.com/embed/zJZKWF7YBas&quot;">https://www.youtube.com/embed/zJZKWF7YBas"</a>; frameborder="0" allow="autoplay; encrypted-media" allowfullscreen&gt;&lt;/iframe&gt;?<br></p>

Means it has converted iframe src

On screen I see it like following.

<iframe width="560" height="315" src="https://www.youtube.com/embed/zJZKWF7YBas"; frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>?

so my question is why wysihtml5 is changing iframe src and how I can stop it?