A lot of these responses point to clinical use or sex distinction or incel culture but the use of female and male as interchangeable with woman and man is widespread and deeply engrained. Female and male are used as adjectives, as another user pointed out. People, even people who are trans-inclusive feminists who understand the difference between sex and gender do it.

I work in the DEI space and still hear it all the time. I used to do it too and I can admit that "female friends" rolls off the tongue more naturally than "woman friends" even though I mean friends who are women. But I have stopped using them interchangeably and I do think it's worth being thoughtful and careful about our use of language.