Max from support reached out to me via email, and here is his solution, which worked like a charm:
"To fix the issue, you could edit the SEO title formats set to your site for items, as now you have the "%p" (the title of your page) set for your blog posts (items), see this video:
https://share.squarespace.com/eDueJeKg
Instead of "%p" (the title of your page) in the Items tab, add "%i" (title of your item).
Check out this guide on title formats:
https://support.squarespace.com/hc/en-us/articles/205814428-Changing-title-formats-for-SEO-and-browser-tabs#toc-edit-seo-title-formats"