Yes, unfortunately the use of liquid metal will inevitably end up voiding the warranty as typically it will instantly short the resistors surrounding the GPU die. Usually, what people will do to prevent this is to put a clear nail polish around the GPU die to try to protect it, but the use of nail polish on the card would void the warranty. Also, since liquid metal can eat away at both the cooler and the GPU die that would be considered physical damage to the card. In general, we strongly DO NOT recommend using any liquid metal on the card.