My best friend from childhood did this to me and my God, it was hurtful. Strangely (or not?) this was also after the death of her father. I was absolutely traumatised and baffled by it, also couldn't work out what I'd done.
I can't say because it would be outing, but when it was finally discussed, it was something so trivial I couldn't even explain it in any way that makes sense. She had taken an innocent, self deprecating comment I'd posted and twisted it into something personally offensive to her. I've never fully worked it out, and even when I played it back to her ten years afterwards, she didn't remember. And I think that sums it up. It was a petulant, somewhat narcissistic move from someone who at that time in their life was going through sone major mental health issues (IMO). I think she was incredibly angry at the world and everyone in it, because of grief, and I got caught in the crossfire.
And it was my first experience of something I have seen more clearly since, which is a lack of emotional intelligence and maturity. Her emotional landscape isn't fully developed and she does exert power over people in these kinds of ways, sadly. I think she's the biggest victim of it though, even though this period of our friendship genuinely damaged and scarred me. If I had any sense, I would probably have just cut her off in return, yet for some reason I couldn't. I guess for my oldest and once closest friend, I sucked it up, in the hope I could help her navigate other interpersonal relationships better. Essentially, like family, I love her and I can't let go.
Back to you - you don't have to take this if you don't want to. I assume that this kind of attention seeking (yes it is - its a petty, aggressive act, done to hurt and provoke a reaction) is the mark of someone deficient. Its up to you to evaluate whether you want that kind of drama and pain in your life. If my experience is anything to go by, this will be a pattern and it will happen again.