SIVA nodes. Sometimes, if you shoot just below the bottom of the crystal part on top, the bullets will just pass right through it without doing damage. The eye/turret things on the Siege Engine. Sometimes shots don't register despite the fact that the crosshair is dead center, and shots can even be seen passing right through them. Have wiped more than once because we couldn't destroy those turrets. Minor bugs, but should still be looked at whenever the dev team has the time.