One of the biggest factors that has led to alleged issues with iPhone X production is said to be a shortage of functional TrueDepth camera components, which are used for Face ID. At one point in the production of the camera hardware, it was said that only 20% of the dot projectors, a critical component for Face ID, were functional. According

Source: Hot Hardware – Apple’s Supply of iPhone X TrueDepth Camera Components For Face ID Is Now Stable Says Analyst