A few days ago Disqus released a featured called "Recommendations" [0]. I haven't received any email about it, and it's enabled by default. It inserts additional HTML on top of the comments, and when I first checked my site I thought that my site had been hacked or something, especially because one of the recommendation was for a different site altogether! [1] It's a Japanese site that I never heard of, does not have similar content to my site, and it's of course on a different domain, so why did Disqus think it was ok to include?
I don't know why Disqus thought it was ok to add HTML and outbound links without even sending an email first. After this, I surely won't use Disqus anymore, and if there was a way to migrate without losing comments I would remove it from my site too.
To make sure recommendations are disabled for your site, go here: https://<your site slug>.disqus.com/admin/settings/recommendations/
[0]: https://help.disqus.com/en/articles/3517730-recommendations
[1]: https://imgur.com/a/i3orUx6