BUG #16954: After install postgresql.service activates but does not activate postgresql@11-main.service

The following bug has been logged on the website:

Bug reference: 16954
Logged by: Aapo Alasuutari
Email address: aapo(dot)alasuutari(at)gmail(dot)com
PostgreSQL version: 11.2
Operating system: Ubuntu 18.04 on WSL2
Description:

I'm trying to install a development environment using some in-house ansible
playbooks. As part of the install postgresql is installed. The installation
commands happen as follows:

dpkg -i ssl-cert_1.0.39_all.deb
dpkg -i libllvm6.0_1%3a6.0-1ubuntu2_amd64.deb
dpkg -i libpq5_11.2-1.pgdg18.04+1_amd64.deb
dpkg -i pgdg-keyring_2018.2_all.deb
dpkg -i postgresql-client-common_199.pgdg18.04+1_all.deb
dpkg -i postgresql-common_199.pgdg18.04+1_all.deb
dpkg -i postgresql-client-11_11.2-1.pgdg18.04+1_amd64.deb
dpkg -i postgresql-11_11.2-1.pgdg18.04+1_amd64.deb
apt-get autoremove -fy
rm -f *.deb
sudo -u postgres /usr/bin/psql -U postgres -d postgres -t -c ALTER USER
Postgres WITH PASSWORD '***';

At the first postgres command the install fails on my WSL2 machine, while it
does not fail on a Ubuntu 18.04 Oracle VBox virtual machine. The reason for
the failure is that there is no socket.

Looking at the postgresql.service, it is active and shows no errors in log.
The latest message is "Started PostgreSQL RDBMS."
However, then looking at the postgresql(at)11-main(dot)service, the service is
loaded but inactive. So far I have not managed to find any errors pertaining
to the postgresql install that would point to any obvious reason for the
failure for the actual service to activate.