Because I was having electrical works being done at home, and I would be at work for the day, I shutdown the Host.
PFSense 2.3 is set to sleep, rather than power off when the host reboots.

When the host powered back up, PFsense woke up.  But didn't check the time (or failed to).  So it was about 8 hours out.

Easy fix, just go and tell NTP to do a time sync.  I can't see an easy way to do that.
Suggestion #1: On the dashboard, in the time/date section, have a link to resync time
Suggestion #2 : In the 'Status' menu, rename NTP to Time.  NTP only means something to people who know what NTP means.
Suggestion #3 : If there is only one NTP server set, do something to advise the user.  Otherwise it's VERY easy to not see that you should have more than 1  server set.  Maybe on the console

I resolved it by restarting the NTP service.  But this seems a little overkill.  I should be able to just resync time
When I restarted NTP at http://firewall/status_ntpd.php
the page it loaded up at http://firewall.igct.local/status_services.php?mode=restartservice&service=ntpd
was actually a HTTP error "504 Gateway Time-out"
The relevant system log entry is

Apr 28 08:37:59 	php-fpm 	19347 	/status_services.php: NTPD is starting up.
Apr 28 17:35:54 	firewall.DOMAIN.local 		nginx: 2016/04/28 17:35:54 [error] 67336#0: *1602 upstream timed out (60: Operation timed out) while reading response header from upstream, client: 192.168.10.55, server: , request: "GET /status_services.php?mode=restartservice&service=ntpd HTTP/1.1", upstream: "fastcgi://unix:/var/run/php-fpm.socket", host: "firewall.DOMAIN.local", referrer: "http://firewall.DOMAIN.local/status_ntpd.php" 

The first line is the wrong time
the 2nd line is corrected time
The NTP logs show

Apr 28 08:19:47 	ntpd 	70007 	Deleting interface #12 pppoe1, fe80::215:5dff:fe0a:4e04%7#123, interface stats: received=0, sent=0, dropped=0, active_time=64013 secs
Apr 28 08:19:47 	ntpd 	70007 	Deleting interface #13 pppoe1, 59.167.198.70#123, interface stats: received=127, sent=129, dropped=0, active_time=64013 secs
Apr 28 08:19:47 	ntpd 	70007 	121.0.0.42 local addr 59.167.198.70 -> <null>Apr 28 08:19:55 	ntpd 	70007 	Listen normally on 14 pppoe1 [fe80::215:5dff:fe0a:4e04%7]:123
Apr 28 08:19:55 	ntpd 	70007 	Listen normally on 15 pppoe1 59.167.198.70:123
Apr 28 08:37:59 	ntpd 	70007 	ntpd exiting on signal 15 (Terminated)
Apr 28 08:37:59 	ntpd 	70007 	121.0.0.42 local addr 59.167.198.70 -> <null>Apr 28 08:37:59 	ntpd 	58240 	ntpd 4.2.8p6@1.3265-o Wed Apr 6 23:07:32 UTC 2016 (1): Starting
Apr 28 08:37:59 	ntpd 	58240 	Command line: /usr/local/sbin/ntpd -g -c /var/etc/ntpd.conf -p /var/run/ntpd.pid
Apr 28 08:37:59 	ntpd 	58347 	proto: precision = 1.200 usec (-20)
Apr 28 08:37:59 	ntpd 	58347 	Listen and drop on 0 v6wildcard [::]:123
Apr 28 08:37:59 	ntpd 	58347 	Listen and drop on 1 v4wildcard 0.0.0.0:123
Apr 28 08:37:59 	ntpd 	58347 	Listen normally on 2 lo0 127.0.0.1:123
Apr 28 08:37:59 	ntpd 	58347 	Listen normally on 3 lo0 [::1]:123
Apr 28 08:37:59 	ntpd 	58347 	Listen normally on 4 lo0 [fe80::1%4]:123
Apr 28 08:37:59 	ntpd 	58347 	Listen normally on 5 hn0 [fe80::215:5dff:fe0a:4e03%5]:123
Apr 28 08:37:59 	ntpd 	58347 	Listen normally on 6 hn1 192.168.10.254:123
Apr 28 08:37:59 	ntpd 	58347 	Listen normally on 7 hn1 [fe80::1:1%6]:123
Apr 28 08:37:59 	ntpd 	58347 	Listen normally on 8 pppoe1 [fe80::215:5dff:fe0a:4e04%7]:123
Apr 28 08:37:59 	ntpd 	58347 	Listen normally on 9 pppoe1 59.167.198.70:123
Apr 28 08:37:59 	ntpd 	58347 	Listen normally on 10 ovpns1 [fe80::215:5dff:fe0a:4e03%8]:123
Apr 28 08:37:59 	ntpd 	58347 	Listen normally on 11 ovpns1 192.168.11.1:123
Apr 28 08:37:59 	ntpd 	58347 	Listening on routing socket on fd #32 for interface updates</null></null> 

All times here are wrong

The WAN (PPPoE) was up at this point in time.

The time was correctly set, even though the page didn't load.