Possible Bug re Marriage

[Proserpine]

I have had this several times recently. I will get a mesaage, something like "Lord Prince Jacobo (my faction heir) has conceived a passion for Lady Margarida whatever, he is willing to pay a handsome dowry for her hand in marriage . . . " etc. The lady Margarida or whoever is a close relative. When I attempt to get her to marry him, it says there are no unmarried suitors in range, even if she is standing next to him.

It seems to me either the message or the marriage is bugged. if the message is valid, the marriage should be allowed; if the message is not valid (because they can't marry), then it should not appear.

I seem to recall some threads about incest, this might be related.