Header tag and paragraph tag are shown in single line tinymce

I’m using TinyMCE in my backend for content entry. But the content are displayed weirdly in the frontend.

I’ve not set any kind of css for this layout.enter image description here

I’m using the following tools and plugins:

menubar: 'file edit view insert format tools table help',
toolbar: 'undo redo | bold italic underline strikethrough | fontselect fontsizeselect formatselect | alignleft aligncenter alignright alignjustify | outdent indent |  numlist bullist | forecolor backcolor removeformat | pagebreak | charmap emoticons | fullscreen  preview save print | insertfile image media template link anchor codesample | ltr rtl',
  toolbar_sticky: true,

This is the project I’m working on.
link

I couldn’t find what is causing the layout issue.