So I made a new category for my blog and noticed this new error message coming up under the Micro.blog -> Account Logs area

Error: Error building site: failed to render pages: open _site/categories/micro.blog-tips-and-tricks/page/1/index.html: not a directory

The name of the category was Micro.blog-tips-and-tricks and after it was generated the path was /categories/micro.blog-tips-and-tricks. This caused that strange error. Renaming the path to /categories/micro-blog-tips-and-tricks fixed the issue.