The liquid in this product is the solution of mineral oil, which has the phenomenon of thermal expansion and contraction. When the weather is cold, there could be bubbles in the liquid, which doesn't mean leakage. When the temperature goes up, the bubbles will correspondingly shrink or disappear.
Prolonged transportation may also lead to the formation of bubbles, which will be smaller or disappear after standing for a period of time. It is an inevitable case, not a product quality problem.
