Why does busybox suddenly go into reboot for no reason?

Question

linux

Busybox goes into reboot all of a sudden. Because of what it can be? How to prevent the occurrence of such situations?
A piece of hardware based on the nuvoton nuc 970 processor.
An excerpt from the log:

Jul  6 11:57:43 (none) syslog.info syslogd exiting
Jul  6 11:57:54 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul  6 11:57:55 (none) daemon.info init: starting pid 543, tty '': '-/bin/sh'
Jul  7 09:59:46 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul  7 09:59:47 (none) daemon.info init: starting pid 543, tty '': '-/bin/sh'
Jul  7 12:30:54 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul  7 12:30:55 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 10 12:12:37 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 10 12:12:38 (none) daemon.info init: starting pid 543, tty '': '-/bin/sh'
Jul 10 13:33:03 (none) daemon.info init: starting pid 707, tty '': '/bin/umount -a -r'
Jul 10 13:33:03 (none) daemon.info init: starting pid 708, tty '': '/sbin/swapoff -a'
Jul 10 13:33:04 (none) daemon.info init: The system is going down NOW!
Jul 10 13:33:04 (none) syslog.info syslogd exiting
Jul 10 13:33:12 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 10 13:33:17 (none) daemon.info init: starting pid 577, tty '': '/bin/umount -a -r'
Jul 10 13:33:18 (none) daemon.info init: starting pid 583, tty '': '/sbin/swapoff -a'
Jul 10 13:33:18 (none) daemon.info init: The system is going down NOW!
Jul 10 13:33:18 (none) syslog.info syslogd exiting
Jul 10 13:33:27 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 10 13:33:28 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 12 11:41:10 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 12 11:41:11 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 13 11:22:44 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 13 11:22:45 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 13 14:00:03 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 13 14:00:04 (none) daemon.info init: starting pid 543, tty '': '-/bin/sh'
Jul 13 16:24:43 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 13 16:24:44 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 14 08:39:19 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 14 08:39:20 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 14 10:38:37 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 14 10:38:38 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 17 10:34:38 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 17 10:34:39 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 17 10:35:10 (none) daemon.info init: starting pid 676, tty '': '/bin/umount -a -r'
Jul 17 10:35:10 (none) daemon.info init: starting pid 677, tty '': '/sbin/swapoff -a'
Jul 17 10:35:10 (none) daemon.info init: The system is going down NOW!
Jul 17 10:35:10 (none) syslog.info syslogd exiting
Jul 17 10:35:20 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 17 10:35:25 (none) daemon.info init: starting pid 573, tty '': '/bin/umount -a -r'
Jul 17 10:35:26 (none) daemon.info init: starting pid 579, tty '': '/sbin/swapoff -a'
Jul 17 10:35:26 (none) daemon.info init: The system is going down NOW!
Jul 17 10:35:26 (none) syslog.info syslogd exiting
Jul 17 10:35:34 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 17 10:35:35 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 17 21:44:04 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 17 21:44:05 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 18 10:36:45 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 18 10:36:46 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 18 15:12:50 (none) daemon.info init: starting pid 1380, tty '': '/bin/umount -a -r'
Jul 18 15:12:50 (none) daemon.info init: starting pid 1382, tty '': '/sbin/swapoff -a'
Jul 18 15:12:50 (none) daemon.info init: The system is going down NOW!
Jul 18 15:12:50 (none) syslog.info syslogd exiting
Jul 18 15:12:57 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 18 15:12:58 (none) daemon.info init: starting pid 543, tty '': '-/bin/sh'
Jul 18 16:50:31 (none) daemon.info init: starting pid 843, tty '': '/bin/umount -a -r'
Jul 18 16:50:31 (none) daemon.info init: starting pid 845, tty '': '/sbin/swapoff -a'
Jul 18 16:50:31 (none) daemon.info init: The system is going down NOW!
Jul 18 16:50:31 (none) syslog.info syslogd exiting
Jul 18 16:50:40 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 18 16:50:41 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 18 17:13:32 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 18 17:13:33 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'
Jul 19 10:55:47 (none) syslog.info syslogd started: BusyBox v1.22.1
Jul 19 10:55:48 (none) daemon.info init: starting pid 542, tty '': '-/bin/sh'

Answer 1

Because of what it can be?

Because of the contents of /etc/inittab? Or /etc/crontab?