Information regarding
this npc.
Will edit with more specific information and logs from the other computer later but here is the gist:
Genni asks you for 550 gold to buy the fire opal. It should be that way - she should get the coin she wants.
HOWEVER...
if you hand her 55 plat she says "I have no use for this, take it back" (i'm paraphrasing) but she keeps your cash. She should either just say thank you and keep it or say what she says and give you money back.