Extra <br/> tag on Heading blocks

[yuanworks]

Describe the bug
Occasionally, when adding new Heading blocks, an extra <br/> will be added to the tag when you press shift+Enter and then delete the line:

Notice from the screenshot that the heading (Future of WordPress) is only one line, and as such, it makes it impossible to delete this extra line <br/> using the Visual editor; the only way to delete it is using the HTML editor.

EDIT: This also happens in regular P blocks too.

To Reproduce
Steps to reproduce the behavior:

1. Create a new Heading block.
2. Press shift+Enter and write some text to add a new line.
3. Proceed to delete the line break. the
   tag will stay.

Expected behavior
Extra <br/> tag should be deleted.

Desktop (please complete the following information):

• OS: Windows 7
• Browser Firefox 60

[ZebulanStanphill]

Duplicate of #5872. Also related: #6021.

[youknowriad]

Closing as duplicate