portmaster and synth report different output

[Luca Ferrari]

Hi all,
first of all I'm new to synth, and trying it on a virtual machine of
mine I got different output:

olivia# uname -a
FreeBSD olivia 11.1-RELEASE FreeBSD 11.1-RELEASE #0 r321309: Fri Jul
21 02:08:28 UTC 2017
root at releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC  amd64

olivia# portmaster -a
===>>> Gathering distinfo list for installed ports

===>>> Starting check of installed ports for available updates

===>>> All ports are up to date


olivia# synth status
Querying system about current package installations.
Stand by, comparing installed packages against the ports tree.
Scanning existing packages.
These are the ports that would be built ([N]ew, [R]ebuild, [U]pgrade):
  N => net/samba46
  N => ports-mgmt/dialog4ports
  N => ports-mgmt/portmaster
  N => ports-mgmt/synth
  N => security/nmap
  N => security/sudo
  N => shells/bash
  N => shells/zsh
Total packages that would be built: 8
The complete build list can also be found at:
/tmp/synth_status_results.txt


So while portmasters is quiet and states it is all updated, synth
reports I need some ports to be installed, such as samba. Please note
that I logged in with zsh, done a sudo and run synth, so such packages
are installed!
Please also note that before running both commands I performed a
dist-clean of all the ports tree (if that matters).

What am I missing?

Thanks,
Luca