Fort Drakon glitch - Warden doesn't react to rescue

My Warden got captured at Fort Drakon and I opted for Morrigan and Leliane to come to the rescue. They bluffed their way past some of the guards, fought guards at the door to the inner fort and near the cells and arrived at the cell where my Warden is, I opened the cell for him and there's a quest marker above his head, Leliane and Morrigan are right next to him, but he's unclickable and won't respond to anything, the Warden's just sitting there with a quest mark doing nothing.

How can I solve this apparent bug?