iPhone X is the one of the biggest projects of Apple planned for 2017, and company has a lot of problems connected with production of this device. Initially company will produce 3 million units of their new smartphone for the day of the premiere, and it was priority for Apple to keep this amount without changes. That's why Apple was forced to reduce accuracy of Face ID, which is responsible for unlocking phone by using our face.
When Apple presented iPhone X, the company said that will have 1000000:1 accuracy, and now after changes we don't know how much accurate will be Face ID. Whole problem is caused by producers of dot projector for iPhone X, which is intended to make face's map basing on 30 000 dots flashed on our face. Premiere of iPhone X will take place on 3rd of November.