I don’t know if this is still an issue for others, but I’m getting it a lot on my computer and my iPhone today. And it also “takes me back”, removing recently typed stuff.
The site has been deprived of my words of wisdom because I’ve given up when I needed to retype parts of posts!
Which may be for the best.
EDIT: a couple of data points: it happened to me posting this twenty minutes ago, and no one else was posting in this thread at the time, but I did have a saved draft. (To my surprise.) That saved draft was from when it happened to me a few minutes earlier in a busier thread, when someone may have been writing at the same time, and it asked me to reload, and I did, but a few sentences had been lost and I decided not to bother. But I had no saved drafts prior to that.