Just got to the part where I rescue Haslin. I have Wyll, Gale, and Shadowheart in my party. I get to the line where he asks "how this is possible". If I select "I think this artefact has something to do with it" the dialog got stuck. Haslin responds, "Hmmmm. that looks very nice. As alien as the mind flayers. The do not belong on this world." Luckily, I had a save just before I initiated the dialog.
I tried multiple things, but ended up finding out that through two sets of answers I was able to hit the 1 key and get a response. This appears to be an issue with the dialog not loading (visually) so the player can select a response.
If you would like more detail please let me know.