We had that after 1975 with the independence of the African colonies, 1 million Portuguese returned to Portugal (some of them never went there and were already born in Africa, like my mom). There were some cases were biracial couples and mulattos and even black couples came to as retornados, but they were a minority. Many men had mulatto children out of the wedlock and left them in Angola since it would be a scandal to bring mulatto children with your wife who you cheated. Many children there never met their Portuguese fathers.
As to colonials returning to Portugal, I only know of the Brazilian colonial elites who used to go to Portugal to study in Coimbra, other than that I don't think they had an interest in moving back to Portugal, but there might be a few cases, but it would be known if there was a big reverse migration between the 17th and the 19th centuries.

