11.3->12.1 upgrade, pwd db not rehashed after adding ntpd user?

[Mel Pilgrim]

I used freebsd-update to upgrade several 11.3-p5 systems to 12.1-p1. 
The etc update process added the ntpd/ntpd user/group.  It showed the 
line changes in the plaintext passwd/group files, but the process 
appears to omit the pwd_mkdb step.

After the upgrade, ntpd fails to start:

# service ntpd start
Starting ntpd.
su: unknown login: ntpd
/etc/rc.d/ntpd: WARNING: failed to start ntpd

Running the usual pwd_mkdb command fixes the issue.