calling "dangerouslyPasteHTML()" with the same value wont always return the same HTML

[philly385]

After applying "bold format" to only parts of a text in the editor, and then calling "dangerouslyPasteHTML()", the whole text becomes bold. I know in the documentation it says:

The snippet is interpreted by Clipboard matchers, which may not produce the exactly input HTML.

But to me this is a bug, so I'm posting this.
Note that this behaviour is also the case for "underline" and "italic" formatting. (This occurs only in my use-case, not in the codepen).

Steps for Reproduction

1. Visit http://codepen.io/wu-philly/pen/GjwbKK
2. Paste: <div><p><strong>Heading (Bold)</strong></p><p>This should not be bold until the user decides to format it bold.</p><p>But instead "dangerouslyPasteHTML()" formats the whole text. </p><p>However it does this all the time. Try to "unbold" everything except the heading and try again.</p></div> into text input.
3. Click "pasteHtml" Button to paste it into the editor.
4. Click again to trigger the bug.

Expected behavior: Calling "dangerouslyPasteHTML()" with the same value should return the same HTML everytime it is called.

Actual behavior: Calling the function for the first time returns the correct HTML. For calling it the second time it has added <strong>-Tags to every node with text.

Platforms:
Mac OSX Yosemite 10.10.3:
Chrome 54.0.2840.59 (64-bit)
Safari 8.0.6 (10600.6.3)
Firefox 49.0.2
Win10 v.1607:
Microsoft Edge 38.14393.0.0

Include browser, operating system and respective versions

Version: quill v1.1.0

Run v1.1.0 to find out