Since I don’t see any actual error messages in this email, I suspect you would be happy with the config.inc.php setting to send email only when there is an actual error:
If this setting is not On, email will be sent for every scheduled task run.
Actually, it’s already on, but I’m still receiving these emails.`
scheduled_tasks = Off
; Scheduled tasks will send email about processing
; only in case of errors. Set to off to receive
; all other kind of notification, including success,
; warnings and notices.
scheduled_tasks_report_error_only = On`
Those messages definitely look like they are just notices, not errors. Are your perhaps on a version earlier than 2.4.6? There was a bug which would have previously caused this: https://pkp.sfu.ca/bugzilla/show_bug.cgi?id=8917