I was playing with a friend yesterday and we couldnt vote on each others dialog choices, this was mentioned in the video too, I dont stream so i didnt know it worked in twitch
Yeah unfortunately what you see in your picture is the twitch integration voting feature. Your friend can still vote in dialogue by having your friend join the dialogue you're having, and click on the dialogue option they prefer. On your end, you'll see their name and the number they choose in the bottom right on the screen, but it's still whomever who's leading the conversation that chooses the dialogue option.