How turns unfold during dialogue
When you hit Talk, it counts as an action and ends the turn immediately, which makes other entities take their turn and move around while you're talking to your target. This is a bit confusing as your target themself might have moved from their previous position, potentially moving out of your character's reach. It also obscurs other potential entities you might have wanted to track the actions of. Still, i understand this decision because conversing isn't instantaneous… and your attention is driven towards something else anyway.
I can see two things you could act upon:
- prevent the entity you're talking to from moving away from you while in a conversation
 - let the turn unfold just before or only once you've ended your dialogue so that you see all actions taking place
 
Optionally if obscuring the actions taking place feels right, i'd suggest going further in that direction and having every dialogue option take up one turn, so that a longer dialogue actually feels like taking more time.