Sure, tl;dr as I understood it:

• Person lists keyboard on Facebook Marketplace
• Gives Meta AI assistant full, 'always-allow' permission to handle the listing, respond to messages about it
• It accepts a lowball offer from someone, tells them to come pick it up at the seller's house without informing seller
• Buyer shows up at the address, waits a while, gets annoyed, leaves and gives negative feedback
• Seller responds in an amusingly earnest way to the bot like 'bro you gotta never do that'
• Meta says it's probably seller's fault for giving instructions somewhere
• Buyer and seller eventually make up and keep doing business