If you are a user that had Portuguese (Portugal) set as your language before, you should go to Preferences->Appearance check your "Interface language/Idioma" and even if it is correct press the save button.
That should fix any issue you might have.
If you are an admin and have users that have set their language as 'pt' (you will see errors on your Sidekiq on some actions related to those users and the language 'pt' being invalid).
If you feel comfortable around PostgreSQL database, you can find all users that have pt as their language doing something like:
select email,locale from users where locale='pt';
Running the code mentioned in the GitHub issue should fix it. Shouldn't be a problem but run it at your own risk :) or wait for a fix
Mastodon é uma rede social baseada em protocolos abertos da web e software livre e gratuito. É descentralizado como e-mail.