Hello t woffer, great Portuguese writing...
There is nothing on Portuguese Labor Code that impeaches an employer to do what you describe.
Two resting days are two resting days, independent if they are holiday or not...
ACT - Autoridade para as Condições no Trabalho is our labor authority and they say that is a "coincidence" if resting days are coincident with an holiday.
ACT contacts on
sabiasque.pt/familia/noticias/2352-denun...resentar-queixa.html
Note: 25th will be Wednesday (4ª feira) and not terça-feira (3ª feira)