While the problem dates from before iOS 9.2's release in December, Apple's acknowledgement of the existence of the issue could mean it will be addressed in iOS 9.2.1 or in the larger 9.3 update, both of which are in beta and expected imminently.
If Apple's manual fix doesn't work, the company is encouraging users to contact Apple support.
For iPhone 6s owners, the battery percentage is likely to be a minor annoyance compared with some of the earlier bugs to affect the iPhone 6s since its release.
A recent beta of iOS 9.3 suggests Apple will also attempt to address criticisms of its Wi-Fi Assist feature, which automatically switches devices to cellular data when the Wi-Fi signal is weak, causing some users to inadvertently exceed their monthly data allowance. iOS 9.3 will now display how much cellular data has been used by the feature.