So obviously that is the problem

Correct.
ShaggyHare67 how come the "installed packages" are now empty ?
They should be automatically filled when executing locally?!
Any chance someone mistakenly deleted them?
Regrading the python environment, trains-agent is creating a new clean venv for every experiment, if you need you can set in your trains.conf :
agent.package_manager.system_site_packages: true
https://github.com/allegroai/trains-agent/blob/de332b9e6b66a2e7c6736d12614de9870eff48bc/docs/trains.conf#L55
This will cause the newly created venv to inherit the packages from the system, meaning it should have the trains package if it is already installed.
What do you think?