During the dispatch of a regular email campaign, Email Experience Manager (EXM) uses only the user's client language for publishing. Sometimes this causes unpublished content in the Web database because an email campaign does not have a version in the user's client language.
This issue affects EXM 3.4.0 and later versions.
To resolve this issue, download and install the patch compatible with the affected product version found on this page:
https://github.com/SitecoreSupport/Sitecore.Support.211150/releases/.