Duplicate meta descriptions

I've just started using a product called SEMRush https://www.semrush.com. It does a bunch of different things, but it identified an error that I cannot track down. I've had some weird things happen with SmartCrawl lately and I'm suspicious that it's coming from there.

The error is that two pages have duplicate meta descriptions. It reports these two pages.

The first links to a genuine Post. The second appears to be just the excerpt of that Post.

The problem is that I cannot locate the second item to edit it (or delete it).

If I click on the first URL, I see the post and I get a menu bar at the top that allows me to edit, etc (a standard WP bar). If I click on the second URL, I get the bar, but no option to edit.

I'm grasping at straws, but thinking it might be related to how Post excerpts are generated for SEO?

I've enabled support on the site.

If you can point me at something, that would be great.

Thanks for anything.