Whenever you change the panel language, it resets to the default Portuguese (Brazil) every hour.

I tested with this; I had English enabled by default, changed it to some other language. Logout, Restarted but the language is still changed. I haven't been able to reproduce. If you can share the exact steps, it might be more helpful.

I just change the language to English, for example, and after a few minutes, when I go back to the easy panel, it's in Brazilian Portuguese again.