i have no idea how this can possibly be a thing, but it is.
recently i have been playing as invisible and the game has not been remembering it when i log on
i had never had problems with it before, only occasionally on joining/leaving parties it would sometimes change itself to online.
it then occurred to me the only thing different is that in this last week i have been playing GW1 a bit.
so i tested it. logging out and in to GW2 retains my invisible status, but if i log in to GW1, when i log back to GW2 my status has changed to online. this happened every single time.
GW1 status doesn’t seem to make a difference as playing offline still changed GW2 to online
be interested to hear from other people if the same happens to them.