When Shopkeeper has two players talking to it, and one player purchases something, the shopkeeper sells them all of the items, and then all of the items downgrade to grey.
Step by step of the bug
Step 1
Login to a Multiplayer session. Doesn't matter which player hosts.
Step 2
Start a game and find a merchant, any of them work.
Step 3
Player 1 talks to merchant, but doesn't buy any items. Continues with the UI up.
Step 4
Player 2 talks to merchant while player 1 is still talking to them. Does not buy any items.
Step 5
Player 1, while player 2 is also talking to the shopkeep, buys any item (generally the augments)
Step 6
Shop keep sells all items despite only one being purchased
When Shopkeeper has two players talking to it, and one player purchases something, the shopkeeper sells them all of the items, and then all of the items downgrade to grey.