This is just a side-effect of how federation works. SDF won't start seeing posts or comments from a given community until someone subscribes to that community from this server. It's only after that's happened that the server bothers to start following what's going on there, so comments and threads from before that point won't be loaded on lemmy.sdf.org

Hi there! Looks like you linked to a Lemmy community using a URL instead of its name, which doesn't work well for people on different instances. Try fixing it like this: !okbuddyphd@lemmit.online