Advantages of combining different references in the one citation

Hi. Actually, it is another question. I am writing a paper and it is happening something weird. For example: the first time I mention a paper it is perfect (Rosa et ., 2016). But the second time the citation changes for Rosa, Borstad, 2016. The references are not duplicate at the end of the paper. But, they are changing inside the text. Could you help me? have you ever seen it?

Thanks,

Dayana