Star Trek: The Next Generation

Comments like this almost make me wish Lemmy had awards

The explanation that I saw is that your home instance doesn’t index every community. Those you see when you search have already been accessed by someone else on your instance. But when you search using the specific community link, your instance now knows someone local wants that community and adds it to the index. So when you search again a little while later, it has been indexed and is in the search results.