Alcohol-type neutral adhesive may have this phenomenon, which is caused by the production of raw materials titanium chromium compound.
Titanium chrome compound itself is red, and the glue of porcelain white color is titanium dioxide in the glue in the role of color.
But glue is organic matter, and organic chemical reaction is overwhelmingly reversible reaction, there are side reactions.
Temperature is exactly the key to causing these reactions. When the temperature is high, there is a forward reaction that changes the color, but when the temperature cools down and stabilizes, the reaction goes back to the original shape.
Production technology and formula grasp well, should be able to avoid this phenomenon.