Need Advice: Moodle generating huge mail relays


Greetings members/guests,
I have a client on my vps who runs moodle on his webspace. Recently I have started receiving mail alerts of huge mail relays. I got them checked from KH support. They referred them as an script error. the possible script that generates errors is CLI. I checked it on internet and found it a cron job activity.
I need advice on whether I should worry about it being resource consuming activity or leave it as it is being non harmful legit relays.
In either cases if possible please help me turning these crons off or at least diverting them to client's own mail address so that he knows what is going on.
If there's no sensitive information in it can you share one of these mail alert messages? Do you see any of these cron jobs listed in the user's cpanel?
I'd worry if these scripts are sending out bulk emails as it's likely going to get your server blacklisted.
Thanks for your response. I have put samples in a PM to you now. But I did not check whether cron jobs are listed in their cpanel or otherwise.