Thank you for understanding. I was playing through night five (finally) and she appeared just as the power ran out, but I never saw her poster either. It might be a random time she can spawn.
I think you are right about it being a random spawn independent of the poster as I remember when beating night 6 and 4/20 mode they appeared multiple times when I wouldn't have had any reason to look at cam 3. I think they even appeared twice in one night as some point.
