iPhone X is slated to arrive on November 3, but Apple and its suppliers are still experiencing reported problems with mass production of sophisticated 3D facial scanning sensors for the handset’s TrueDepth camera, according to a report Tuesday by Japanese outlet Nikkei.

It’s not entirely clear if poor 3D sensor yield rates will have any material impact on launch supply although the publication cited two executives working for iPhone suppliers as saying that part makers are still struggling to reach a satisfactory yield rate for the component.

Yield, the number of good units produced versus the number of total units going into the manufacturing process, if poor, could easily damage Apple’s margins and bottom line and potentially hurt its ability to fulfill iPhone X preorders by the end of the year.

Both sources were unable to offer clarity on whether Apple could meet large orders after iPhone X’s launch. One of the sources said that iPhone X was being churned out in small quantities, around some tens of thousands daily.

Analyst Jeff Pu has identified 3D sensors as the only major issue left in iPhone X production.

Pu added that he expected mass production of iPhone X in the second week of October and that first shipments would begin to leave China for global distribution a week later. “Supply will still be tight after November 3,” he cautioned.

Foxconn has already produced about two million iPhone X units this month and is planning to boost production to ten million units the following month.

Apple analyst Ming-Chi Kuo estimated that demand for iPhone X pre-orders may surpass 40 million to 50 million units. “We think Apple’s (US) core fans and some iPhone 6 and 6s users are willing to pay a hefty price for this upgraded device,” he wrote in a recent not to clients.

Kuo, too, blames the production bottleneck on the phone’s new TrueDepth camera system, which has a “complex construction“ and will “therefore be harder to achieve mass production.”

At least we now know that Apple has been able to finally solve other manufacturing issues that have been plaguing its flagship handset for months now. The biggest question for Apple is, of course, just how many people are waiting for iPhone X, more so in the wake of a somewhat muted response to the iPhone 8 launch.

At any rate, it looks like iPhone X will be initially hard to find.