I have had this happen to me also. It usually happens when one of my companions, mainly Lazeal, gets into a side conversation with some other NPC while I am in a dialogue cut scene. It has happened with the Druids with Kagha, the 'Teethlings' in the grove, the Zhent folks, and the Gobos in the deserted village. Lazeal seems to have a problems with everyone. It's made me leave her in camp most of this run through. When in a cut scene dialog, check to see if any of any of your companions have conversation bubbles on their pictures. If you do, trey to switch over to that companion as quickly as possible to avoid confrontation. I hope this helps you a little.