This is an issue for ranged units concerning objects such as burrows where you target the burrow, but cannot hit it because another part of that burrow obstructs your ranged attacks, obviously this can be extremely frustrating in say dungeons like AC where you often have to destroy these burrows but the only way to hit them is your barrage skill or be lucky not being obstructed. This problem is not limited to just burrows but also happens with other likewise objects.