the Router is not rebooting

I have MikroTik RouterOS 4.16 running on a RB450G.
This script runs once a week on Sunday morning. Every second Sunday it fails to start properly and I get to visit my office at 2:30am.
Here is my script.

 name="system_reboot" owner="admin" policy=ftp,reboot,read,write,policy,test,winbox,password,sniff,sensitive run-count=0 source=
       :log info "starting weekly reboot"
       /tool e-mail send \
       \tto="rlcalhou@x.org" \
       \tsubject=([/system identity get name] . " weekly REBOOT at " . [/system clock get time]) \
       \tfrom=wireless@x.org \
       \tserver=64.8.xx.xx \
       \tbody=(Scheduled [/system identity get name] . " weekly reboot has been initiated.") 
       
       :log info "email sent to wireless@x.org"
       :delay 10s
       /system reb
       y

I’ve looked at the system log and couldn’t see any of the log entries from this script.

This same script works fine on a RB750G.

Any help would be appreciated.
Thanks!