We discovered a bug on this weekend with our last newsletter. We use CiviMail to send our newsletter to all contacts within our "Newsletter" group. As usual we collected the group as the recipients in the mailing form. After the update to CiviCRM 5.29.1 we made last week we realized that the newsletter was sent to group members which are delete already.
I checked if these contacts were included to the newsletter recipients before but I did not find deleted contacts in the list of recipients for newsletters sent before this update.