Mona on Fort Joy bugged?

[TheOne]

So i met this sick woman called Mona in a tent around Fort Joy. When i speak with her with one of my party members she has a few lines of dialogue, and if i choose some specific ones that party member cant talk to her anymore.
However i've seen online that she is suppose to bet the necromancy vendor, but i cant get her to sell me anything, there is no dialogue that enables that. Is she bugged?

[zoro's housewife]

Just start a dialogue with her, and then click on the barter tab at the top left of her box, near her portrait.

[TheOne]

Thanks, totally forgot you can do that. All the vendors i met until now WANTED to sell me stuff, so that trading option appeared in dialogues. But, Mona is a special one...