Sadly, no one is being shocked at seeing two words “her girlfriend” in the same sentence anymore...
It IS possible “girlfriend” means just that (in the old fashioned sense). That’s the way I read it. But I’m inclined toward the old fashioned America where things made sense.
I get your point, but from my experience, it’s fairly common for women to refer to each other as ‘My Girlfriend’.
However, I am still getting used to hearing or reading the phrase “Her Wife”. That term can have only one meaning. I have to ‘recalibrate’ each time that comes up.