After the excitement of another huge launch, Apple is finding there are some issues with a small number of its new models.

The New York Times and USA Today are reporting the company has found some of the new 5S iPhones have a defect that will cause the battery to drain quickly.

The company says its reaching out to customers with the affected phones and will provide them with a replacement. The defect does not affect the safety of iPhone batteries.

Apple did not say how many iPhones were defective, but if they are reaching out to them in person, that number might not be too large. In September, Apple said it had sold nine million new iPhones in the first weekend they went on sale.

A manufacturing issue is not the same as a defective battery, which some users thought was the problem with their phones.