Dear Ulrich,
Running the command sudo apt autoremove --purge dbus-user-session, as you suggested, does not solve the issue.
Just to be clear: When connecting via X2Go with Session type : Local Desktop the issue is not present. Equally via VNC. Only when connecting via X2Go via
"Custom Desktop" this will start a NEW session and results in different permission issues, including Seahorse not showing passwords.

Help would be much appreciated.

Am Sa., 12. Okt. 2019 um 21:44 Uhr schrieb Ulrich Sibiller <uli42@gmx.de>:
On Sat, Oct 12, 2019 at 5:28 PM Alexanderstr Miete
<alexstrbonn@gmail.com> wrote:
> Help would be much appreciated.  How can Seahorse get the same privileges during that X2Go session as for a local session/VNC?

Hmm, have you tried this?
https://askubuntu.com/questions/931780/passwords-missing-from-seahorse-passwords-and-keys

Uli