Regulars lounge partially visibile bug?

I’m testing a new Discourse installation with some users and am experiencing something odd.

The default “Regulars Lounge” category works fine for me (admin). But, the TL3 users don’t see any topics when they navigate to it (it does appear on their list of categories). Moreover, they do see the posts of that category appearing on their latest (or through search), so they do have permissions to see them (and to post on those topics). The only issue is that the category appears totally empty to them when they visit it.

Perhaps relevant, I used rake export:category_structure and rake import:file to bring the category structure from a previous test forum into this one. On the previous one, everything worked as expected.

What should I be looking into to debug this?