repeating H1's in source code

I asked SEMRush why my site audit flags duplicate H1 and title tags for every post. The rep did a Jing video and says it shows the problem in the source code. This is near the bottom of the page of code:
<header
class=”entry-header”><h1 class=”entry-title”>Name of my real title</h1><div
class=”comments-link”>. The title appears 5 times in the source code. It’s not something I added, it’s just WordPress stuff. I don’t think a class name would be interpreted by Google as duplication–would it? I’m using Twenty Twelve. I don’t add any H1s, since the title is automatically H1. Google Search Console/WMT doesn’t show any errors relating to this. Thanks for any help.

[closed as duplicate – please continue at https://ww.wp.xz.cn/support/topic/semrush-flagging-twenty-twelve-source-code-for-h1s?replies=1 ]