Will h1 tags hurt my SEO?
The Also Bought widget title may be set inside an <h1> HTML tag.
Urban legend says that having multiple <h1> tags is bad for SEO but that is not true.
Multiple <h1> tags are perfectly correct following the HTML5 specification and will not have any negative effect on SEO.
You can see a detailed discussion on the issue at https://www.greenlanemarketing.com/blog/seo-101-seo-and-multiple-h1-tags/ and a response from Google at https://productforums.google.com/forum/#!msg/webmasters/BmyI8YX_25A/81hZNQFJDQAJ