I thought this issue had resolved itself but looks like I was wrong. Just had another unexpected reboot. Nothing in the logs and nothing captured via serial console messages.
Oct 14 08:10:12 php /usr/local/pkg/apcupsd_mail.php: Message sent to walterstarks@icloud.com OK
Oct 14 08:11:25 apcupsd 33988 Communications with UPS restored.
Oct 14 08:11:27 php /usr/local/pkg/apcupsd_mail.php: Message sent to walterstarks@icloud.com OK
Oct 14 13:10:02 snort 33227 invalid appid in appStatRecord (4385)
Oct 14 14:25:00 snort 33227 invalid appid in appStatRecord (4385)
Oct 14 16:30:01 php-fpm 22709 /diag_backup.php: Successful login for user 'backup' from: 10.0.1.20 (Local Database)
Oct 14 18:24:06 syslogd kernel boot file is /boot/kernel/kernel
Oct 14 18:24:06 kernel Copyright (c) 1992-2018 The FreeBSD Project.
Oct 14 18:24:06 kernel Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
Oct 14 18:24:06 kernel The Regents of the University of California. All rights reserved.
Oct 14 18:24:06 kernel FreeBSD is a registered trademark of The FreeBSD Foundation.
No idea where to go from here. ❓