I believe the simple answer is that you can only see hashtags for toots that your server knows about. So if you subscribe to a hashtag you will see anything from the Federated timeline with that hashtag also in your Home timeline.
I believe the simple answer is that you can only see hashtags for toots that your server knows about. So if you subscribe to a hashtag you will see anything from the Federated timeline with that hashtag also in your Home timeline.