Bug in Heading 1 – no new line after it

If you have text formatted as Heading 1, then it looks fine in the visual editor. But when the post is displayed, the subsequent text follows the heading without going onto a new line.
To replicate the bug:
1. Create a post with this text in it:
<h1>Heading 1</h1>
<h2>Heading 2</h2>
2. It looks perfect in the Visual editor:
Heading 1
Heading 2
3. Now publish and look at the post, it looks like this:
Heading 1 Heading 2

Thanks.