It seems like the whole feature is running wrong and should probably be hidden until it can be reexamined. Because every Lemmy server seems to have “trending communities” that are just empty new communities or are just single-user bot feeds. And those are fine uses of lemmy! But they’re not “trending”.
You might have better luck with https://feddit.nl/c/trendingcommunities
!trendingcommunities
!trendingcommunities@feddit.nl for folks who want to go straight there.