Hello, Duarte,
Solved.
It is because your excerpt contains tags, and when a part of the excerpt is taken to show some unclosed tags caused the problem. Keep the Show Excerpt option disabled https://prnt.sc/KULQLZ6zKCMQ or edit the description of products. You can add a few words in the Short description area, without tags, then the content will be displayed just fine.
Best regards,
8Theme’s Team