In my default lect, adjective agreement (-a instead of -u) with nouns designating persons of female sex is never obligatory but possible with some adjectives as for instance bunitu/bunita 'pretty'. In this (basi)lect, nouns designating things don't have gender. So there can't be any adjective agreement either.
Source: Brüser et al. 2002: s.v. brisi
Source: Brüser et al. 2002: s.v. manera
Source: Brüser et al. 2002: s.v. bexóna