OK, so I finally found the fix.
I uninstalled metasploit ( sudo apt-get remove --auto-remove metasploit-framework ) and then re-installed the new build from their github repo. Installed it in my /opt folder and then installed all the dependencies (a bunch of ruby gems that will probably need some manual dpkg installs themselves) and now it works.
I guess the defualt Metasploit just didn’t work and upgrading it also didn’t.