Chrome Version       : 55.0.2883.87
OS Version: Ubuntu 14.04.5 LTS
URLs (if applicable) : - 
Other browsers tested:
  Add OK or FAIL after other browsers where you have tested this issue:
  Firefox: 50.1.0 OK

What steps will reproduce the problem?
1. Open data:text/html,<script>t = document.createElement('template');t.innerHTML = '<form action=foo></form><form action=bar></form>baz';console.log(t.content)</script>
2. Look into the console and inspect the logged document fragment

What is the expected result?

The forms foo and bar are not nested.

What happens instead of that?

The form bar is nested in the foo form, with the closing form elements being appended to the end of fragment.

This parsing flaw happens only when parsing within the <template> elements i.e. it does not happen for document.implementation.createHTMLDocument() or data:text/html documents. It looks like an implementation error of

https://html.spec.whatwg.org/#reset-the-form-owner

See also:

https://html.spec.whatwg.org/#the-element-pointers (form element pointers are ignored in template elements)
https://html.spec.whatwg.org/#creating-and-inserting-nodes


UserAgentString: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36