New form tokens cause XHTML validation error when more than one form present on a page

I am very thorough on keeping errors on my xhtml to as close to 0 as possible. To this end i keep a copy of a validation plugin installed within firefox that alerts me to potential errors with my markup.

4.7.3 i had near 0 errors for almost all of my pages (all viewable public pages were error free). Upon upgrading to 4.7.4 i noticed one error. Checking this further reveals the following :-

... anchor "..." already defined
Cause:

An anchor with the same name is already defined. Each anchor should be unique.
Solution:

Choose another name for the anchor or modify the previous one.

References:

Anchors: http://www.w3.org/TR/html4/struct/links.html#h-12.2.1

The anchor in question is

<input type="hidden" name="edit[form_token]" id="edit-form_token" value="457943807165e6dda10d4c31f941ded1" />

It is defined in two places on the markup, by the submit button on comments and further tests reveal a new version of it has been added under the comments control dialogue, whcih we have enabled, that was not present on 4.7.3, thus causing the error. Reverting my test site to 4.7.3 sees the error disappear and only once instance become again available.

I'm keen to get back to 0 errors once more so commit this bug for further investigation