Some Apple iPhone 6s owners are experiencing a battery percentage freezing bug. The error causes an effected phone's battery readout to remain stuck at a certain percentage and fail to update when the battery drains.

Apple has already begun investigating the bug, which is causing some iPhone 6s and iPhone 6s Plus owners to unexpectedly run out of juice, CNet reports.

This is not the first bug that has come to light in the batteries of iPhone 6s and iPhone 6s Plus models. When the new iPhone was released in September, it was revealed that the phones were constructed with two different chips, leading to drastically different performances in battery life. While Apple admitted that the difference in the chips could affect the battery, they claimed the difference only led to a 2 to 3 percent change in performance.

The latest bug does not affect the actual battery life a user gets, but it does cause some confusion about when the phone needs to be charged.

Timezones and Clock Adjustments

The battery percentage bug seems to be closely related to the phone's clock. Users who have traveled across the country into a new time zone or those who have manually adjusted the clock have been experiencing this issue.

A user on Reddit says that he experienced the issue but realized that it was because he had changed his clock. He added that once he stopped adjusting the clock, he no longer experienced the issue.

Apple Says Use Automatic Clock 

Apple tells users to avoid manually changing the clock. The company says to go into settings and turn on the automatic time setting instead.

The company is looking into a fix for the bug. Usually Apple waits until an iOS update to send out such fixes. The next iOS update is iOS 9.3, but that is not expected until Spring, so Apple might have to release a specific fix sooner.