The bug happens when you try to sail to merchant boat as a scripted NPC intercepts you.
In the very start of the game when you leave the first island (Port Maje) you are intercepted by a Pirate. I saw a merchant vessel and thought i would just kill then real quick first, but my boat was a little to slow so the pirate boat got to me first. Every thing loaded and the scripted interaction was about to begin when a dialog box comes up asking if i want to 1 "show me what you have for sale." 2 [Attack] 3 [Leave.].