Clicking on a hash tag opens other instance page
I think this behaviour is from GNU Social.
In mastodon if you click on a hash tag it will open the hash tag in a pane showing all the posts in the federated timeline with that particular tag.
I think its a nice feature to have and it is super annoying to go to visit other instance pages especially if you have JS blocked for other sites. Its also annoying to open a new webpage for every click on hash tag.