Yes something like that happened to me, more or less. I can't say we were "friends", but we chatted from time to time about totally innocent things, like classical music, and then - all of a sudden and for no apparent reason - I was blocked. 😐
I asked some other users about that, and they said she's known to be somewhat unstable.
Never heard of her again. Don't even know whether she's still on SW or not.