The basic tetrode tube symbol has a bug, the cathode cannot be connected.
Can you please give a little more details on the issue? Are you using scheme-it or is this a Ki-CAD issue?
I use Scheme-it on the Digikey web site.
If you place the basic tetrode tube on the page,
you cannot connect to the cathode.
All the other tubes (tetrode and other) seem ok.
Yes I was able to verify this is not working correctly. I will submit this to my team to update. As a temp solution you can put a “Port PIN Bottom” in its place and that will give you the connection for the schematic. - Robert