The Divi theme has well-known issues when it comes to site search and results. Divi uses short-codes for post formatting, and some search plugins do not execute the short-codes - like a web browser does - but present search results from the database. So you will see unexecuted short-codes and other formatting coding in search results when using plugins that access the database for search results. This same issue occurs with other similar themes and many "page builder" plugins that also use short-codes for design and formatting.
The default WordPress search does not have this issue with Divi; but the default search engine does not provide results sorted by keyword, only by date, which is an issue when you want keyword relevancy in results, and/or live results, as with the Algolia plugin.