Those look the same to me if I make the sorts the same (e.g., sort both by new). Pretty sure the first image in your post is looking at the version on Lemmy.world.
Hi there! Looks like you linked to a Lemmy community using an URL instead of its name, which doesn't work well for people on different instances. Try fixing it like this: !hackernews@lemmy.world, !hackernews@derp.foo
Looks ok to me (visiting through lemmy.world as in your first screenshot). However there was a bug before the upgrade to 0.18.1 where sorting by anything other than "new" was hiding posts for whatever reason, and looking at the footer in that screenshot you did take it before the upgrade, so it was possibly that.
If you're still seeing the community as empty now, double check your account settings and make sure you're showing read posts. Because they are 100% there from a .world point of view :)
In that community all the posts are tagged as "english". Since most people don't bother explicitly setting their language, I'm gonna guess that's been set at the community level.
Your post here isn't tagged with a language, because the community isn't forcing one.
SO. Is it possible you only have "undetermined" selected in your language settings, and not english? It's a multi-select so you can choose all the languages you speak (plus undetermined) by ctrl-clicking each one.