Nut upsuser - Jan 2020 - upsmon -c fsd command in pfsense master does not shutdown Synology slave

I have pfsense set as the NUT master and my Synology NAS as a slave client.

I tried recreating a shutdown sequence by issuing a /usr/local/sbin/upsmon
-c fsd command in pfsense (so as to preserve battery lifetime while testing
all these) but the weird thing is that my Syno doesn't seem to get a hold of
the FSD event. My pfsense master and UPS shuts down properly though. As soon
as I issue the FSD, the /var/log/messages in my Syno says this:

2019-12-31T02:05:03+08:00 Synology synoups: [UPS] Check Boot Status.
2019-12-31T02:05:03+08:00 Synology synoups: WARNING: UPS is On-Line

But when I recreate the shutdown sequence by unplugging the mains, all goes
well and the Syno picks up the OB LB FSD event properly. Does this mean that
Syno needs to see that the UPS is in OB LB state to issue a shutdown even if
it sees an FSD event already?

OS name and version: pfsense 2.4.4-RELEASE-p3 @ FreeBSD 11.2-RELEASE-p10

exact NUT version: pfsense package 2.7.4_7

NUT installation method: from source tarball, package or Subversion: pfsense
package manager

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