Yes. But the file is in UTF-8 because it has some UTF-8 in the comments. A PEM certificate itself is simple pure 7 bit ASCII thus I guess it doesn’t like the UTF-8 in the file. If you make a copy of the file and remove the comments you’ll probably get it imported.
But again: you don’t need the ca-bundle. I am pretty sure, that simply enabling “Verify SSL” on a repository effectively does exactly the same. Unless you specify a specific CA certificate to use, the ssl libraries will use the system default, i.e. the ca-bundle to verify the https connection. So don’t set it. Don’t use it. If you want to be sure you can try to setup a repository pointing to a self-signed webserver to check if it is accepted or not when “Verify SSL” is enabled.
Importing ca-bundle is pointless and it also won’t accept any changes anymore which are automatically added to ca-bundle in the system.
Yes. It’s happily syncing every day and getting new updates every couple of days. But again, I am still on pulp2.
I don’t think that shows you whether you use pulp2 or pulp3. Your error messaged show pulp3 thus I guess you have made the pulp3 migration.