I do run a blog with ghost and have set up discourse with the official docker setup.
Then I used the ghost discourse integration in order to have comments on my blog via discourse.
Works fine except that when you disable this flag Imported topics will be unlisted until there is a reply. discourse will also import blog posts that are still in draft mode.
It’s not a bug per se - Discourse will import any topic it finds that meets the import criteria. It should remain unlisted though until you publish it. Does that not work for you?