I activated Auto fill in regional dialects in my project, and I have Portuguese at 62% ready but when I download my translation Portuguese Brazilian is 0%, and all full of English sources. Maybe I need to do something else to enable this option and checkbox is not enough?
Portuguese Brazilian is a stand alone language in Crowdin. I think this one and 2 or 3 others that may be known like dialects are not dialects, at least in Crowdin. Maybe Brazilian people requested this, don’t know the reason of such behaviour, but it is as it is.
Try creating some custom language that would be Portuguese dialect. Or just upload translation from Portuguese into PT-Brazilian with language code changed in translation file.