I have no helper languages configured. The only thing I have (because I never changed it) is the text "default" in the language codes.
The recent changes in fallback behaviour and features has caused this. I have fixed it in mwr:96177 which you already confirmed as fixed. Thanks for the report!
Thank you for the fix and the quickness :).
Quickfix would have been to remove 'pt-br' from 'pt'.
