Yes, unfortunately that's a known issue. In the latest version of the app, you should see the translation percentage for every lesson in the main menu. As translations are community contributed, we depend on native speakers of your language to re-complete those. When I have a bit of time, I will participate in the French (which I've recompleted for this release), Spanish, and Japanese translations. But while I used to speak Portguese it's been a long time without practicing and I'm too rusty to do a good enough job on it.
If people want to participate in the translations, they find instructions here.: https://github.com/GDQuest/learn-gdscript-translations#readme