Aha - I've worked out why the choices are vanishing, I'll upload that as a 0.1.1 in a minute. Thank you.
I am struggling to re-create the loop but I will keep trying!
I do expect most players to exhaust all other options before saying "I can't help you", but also provide the option to short-cut the conversation. Certainly there's no intention to create an inescapable loop here.