This is a bug.  She showed up in my camp as well like that.  When I spoke to her I got dialogue options as if I had already met her (solo run, had spoken to none of them.)  I reloaded and ignored her, then on the second long rest after this I got the dialogue I was supposed to have with her showing up uninvited.
Still interested in if this happened to anyone else with the others (besides Wyll now.)