Strange attempted emails from Cron

I use Zoho for my email client and last night I got a couple of notifications saying:

Warning! Unverified sender. The system could not verify if this email was sent by [email protected]. Do not click any links or open any attachments, if any, in this email.

The first one was the following:

subject: Cron <root@servername> test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )
message: run-parts: /etc/cron.daily/do-agent exited with return code 100

and then about an hour later:

subject: Cron <root@servername>    cd / && run-parts --report /etc/cron.hourly
message: run-parts: /etc/cron.hourly/droplet-agent exited with return code 4

Not sure what to make of this. At first I thought someone gained access to my server. But I am not really sure. I am by no means an expert on the server side. This is just my DigitalOcean droplet that I do mostly development on and host a couple personal sites.

So since the message had run-parts: in it if figured I would check out the cron jobs. Here is the contents the cron.daily directory .placeholder apport apt-compat do-agent dpkg logrotate man-db and the cron.hourly folder has the following in it .placeholder droplet-agent. I don't see anything crazy here.

So then looking at the first email I see test -x /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily ). But I don't have anacron in my /usr/sbin/ directory.

Does anyone know what is going on here? Is this something I should be worried about? Why am I receiving these emails? I haven't done anything new on here in a quite a while so it's not like I added something new or anything like that.

Update:

Contents of /etc/cron.daily/do-agent

#!/bin/sh
/bin/bash /opt/digitalocean/do-agent/scripts/update.sh >/dev/null 2>&1

Contents of /opt/digitalocean/do-agent/scripts/update.sh

#!/bin/bash
# vim: noexpandtab

REPO_HOST=https://repos.insights.digitalocean.com
REPO_GPG_KEY_CURRENT=${REPO_HOST}/sonar-agent-current.asc

main() {
        # add some jitter to prevent overloading the packaging machines
        sleep $(( RANDOM % 900 ))

        export DEBIAN_FRONTEND="noninteractive"
        if command -v apt-get 2&>/dev/null; then
                curl -sL "${REPO_GPG_KEY_CURRENT}" | apt-key add -
                apt-get -qq update -o Dir::Etc::SourceParts=/dev/null -o APT::Get::List-Cleanup=no -o Dir::Etc::SourceL>
                apt-get -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" -qq install -y --only>
        elif command -v yum 2&>/dev/null; then
                rpm --import "${REPO_GPG_KEY_CURRENT}"
                yum -q -y --disablerepo="*" --enablerepo="digitalocean-agent" makecache
                yum -q -y update do-agent
        fi
}

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