I have encountered an apparent bug in The Cornett's Call. I was asked to meet Dereo in the Delver's Row. I did not do this for a while, completing other quests first and never entering Delver's Row. I just entered Delver's Row and made my way to the thug on a bridge who guards Dereo's lair. My journal tells me that there should be a dialogue option for me to state that Dereo has called for me. However, this dialogue option does not appear. I can ask the thug a few questions, but in the end it comes down to either leaving or attacking him. How to fix this?