Salesforce Emails Show Private But Einstein Activity Capture Set To ‘Share with Everyone’

The solution for emails not showing as shared, is to refresh the Sharing Settings to apply the changes for all of the emails that were captured via Einstein Activity Capture.

Refresh the Sharing Settings for Users (email owner and email viewer)

1. Click on your avatar, then click on Settings.
2. On the left pane, expand Email | Einstein Activity Capture | Settings.
3. On the Sharing Settings for All Emails and Events, select Don't Share.
4. Refresh the page.
5. Set the value again for Sharing Settings for All Emails and Events to Share with Everyone.