switch to another brand than. are you 100% certain they are not fake? are your security stickers clear( fakes)? I ahve yet to see an underfill and I always checked by using the 10cc syringe. can shorts happen? certainly on every product made but i personally have never experienced it and was certainly not trying to piss you off or accuse you of anything. also are they shrink wrapped? if not check the bottom of the bottle to see if the glass has been smoothed over as folks have been known to remove oil from the bottom of the bottle and refilling with another product if that makes sense.