Remiders went crazy

I got a bunch of emails this morning stating that i send a client an invoice reminder for a late payment many times seems one per hour. Below is an edited copy of my activity log

26-Sep-2016: My Name emailed invoice O-0032 to Some Company
26-Sep-2016: My Name emailed invoice O-0032 to Some Company
26-Sep-2016: My Name emailed invoice O-0032 to Some Company
26-Sep-2016: My Name emailed invoice O-0032 to Some Company
26-Sep-2016: My Name emailed invoice O-0032 to Some Company
26-Sep-2016: My Name emailed invoice O-0032 to Some Company
26-Sep-2016: My Name emailed invoice O-0032 to Some Company
26-Sep-2016: My Name emailed invoice O-0032 to Some Company
26-Sep-2016: My Name emailed invoice O-0032 to Some Company
25-Sep-2016: My Name emailed invoice O-0032 to Some Company
25-Sep-2016: My Name emailed invoice O-0032 to Some Company
25-Sep-2016: My Name emailed invoice O-0032 to Some Company
25-Sep-2016: My Name emailed invoice O-0032 to Some Company
25-Sep-2016: My Name emailed invoice O-0032 to Some Company
25-Sep-2016: My Name emailed invoice O-0032 to Some Company

Please check the cron is once a day

Right i had it set to once per hour, now it is once per day, it is ok to have send-invoices set to once per hour right?

2 * * * * root /usr/bin/php /var/www/ninja/artisan ninja:send-invoices
#2 * * * * root /usr/bin/php /var/www/ninja/artisan ninja:send-reminders
0 8 * * * root /usr/bin/php /var/www/ninja/artisan ninja:send-reminders

Yes, send invoices can be hourly.