Rewrited content shouldn't be problem. Unless you have directly copied and paste it.

Excerpts*are quite a common and widely used thing, and besides these are insignificant pieces of text, so they shouldn`t be a problem at all, not in terms of duplicate content.

Duplication issues may be the case if you copy any content in full or steal content, or, most commonly, if you have issues like duplicated www/non-www or http/https versions with no proper redirection, and the same page is available under two URLs that are different in the eyes of Google.

Every time you get another excerpt, you're changing the content of the home page, hence, what Google thinks the page is about, hence what it will rank it for.

Unless all the posts are about the very same keywords.