Einhar hideout talk options includes those about not yet encountered masters.

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Einhar have been added at Act 2 SSF Betrayal playthrough into my existing hideout (which was acquired and decorated much earlier during Legacy playthrough). For some reason he has all the talk options about some other masters that never have been met nor invited to hideout by my current character (Zana, Nico, Alva). Some of those (Nico, Alva) are also unmet by other characters as well.

In a similar note, Zana in Standard SSF has dialogue about Cavas. Unless I've not been looking hard enough, Cavas is not involved in Standard at all this league thus cannot be met.