Does the yellowing on the lid of the Xiaomi Multifunctional Hot Pot Cooker 6L affect normal use?

It will not affect the normal use. The lid of the Xiaomi Multifunctional Hot Pot Cooker 6L uses stainless steel, which is food-class material.
Water stains remain. The water contains minerals such as calcium and magnesium. After the water evaporates, these minerals will remain on the metal surface to form scale, causing the surface to turn yellow. It is impossible to completely remove it and has no effect on use.
Note:
After each use, rinse the hot pot cooker while it is still warm. If there are stubborn stains, add appropriate amount of detergent, white vinegar, baking soda, citric acid, etc. to warm water and soak the hot pot cooker in it, then rinse it with clean water and finally dry it. It is recommended to place the product in a ventilated and dry place.