Double timestamps in logs

I noticed some double timestamps in my logs recently. They started just after I upgraded the host to FreeBSD 12, but I am not convinced they are related.

This is from /var/log/messsages:

Jan 22 21:41:40 knew 1 2019-01-22T21:41:40.760533+00:00 knew.int.unixathome.org pkg 89351 - - py36-iocage-devel upgraded: 1.0.0.20181219,1 -> 1.0.0.20190122,1 

They started late yesterday, this is from /var/log/maillog:

Jan 21 22:28:58 knew 1 2019-01-21T22:28:58.677083+00:00 knew.int.unixathome.org postfix/anvil 42521 - - statistics: max connection rate 1/60s for (smtp:10.55.0.3) at Jan 21 22:25:38

You see that I have both:

Jan 21 22:28:58

and

2019-01-21T22:28:58.677083+00:00

Googling did not help

Restarting syslogd did:

$ sudo service syslogd restart
Stopping syslogd.
Waiting for PIDS: 834.
Starting syslogd.

A quick test:

$ sudo pkg install -f py36-iocage-devel
Updating local repository catalogue...
local repository is up to date.
All repositories are up to date.
Checking integrity... done (0 conflicting)
The following 1 package(s) will be affected (of 0 checked):

Installed packages to be REINSTALLED:
	py36-iocage-devel-1.0.0.20190122,1

Number of packages to be reinstalled: 1

Proceed with this action? [y/N]: y
[1/1] Reinstalling py36-iocage-devel-1.0.0.20190122,1...
[1/1] Extracting py36-iocage-devel-1.0.0.20190122,1: 100%

And /var/log/messages seems OK now:

Jan 22 22:13:21 knew syslogd: exiting on signal 15
Jan 22 22:13:21 knew syslogd: kernel boot file is /boot/kernel/kernel
Jan 22 22:13:53 knew pkg[72931]: py36-iocage-devel reinstalled: 1.0.0.20190122,1 -> 1.0.0.20190122,1

And so does the mail log:

Jan 22 22:16:56 knew postfix/anvil[72611]: statistics: max cache size 1 at Jan 22 22:13:36

Anyone have any idea what was going on here?