I have noticed that this map (Lagonian Port; Divine Era) hitches and lags whenever I play a class that uses pets in volume. I am currently playing a Lich build that uses ‘Wandering Spirits’ and, on this map, when a higher density of spirits is summoned, the hitching/lag becomes very noticeable.
As far as minions/pets, I believe the issue has something to do with pets trying to access areas of the map that are fenced in, causing them to essentially bump up against the fence. This causes a hitching that is noticeable in my character’s movement… a resulting stutter-step. This clears up as the minions/pets despawn.