By AppleInsider Staff

Published: 10:50 AM EST (07:50 AM PST)

A benign software bug is causing some of Apple Inc.'s iPhone handsets to reflect an incomplete battery charge when in fact the battery is properly charged to capacity, the company says.

Over the past two weeks, a significant number of early adopters have report that their iPhones will not indicate a full charge no matter how long they are left plugged into a power adapter.

"Your battery is fully charged, but the UI (User Interface) is just not correctly reflecting this," an Apple spokesperson told WirelessInfo. "We expect to fix this in a software update."

Apple, which has yet to publish any information on the issue publicly, declined to say when the software update would be released.

In following the issue closely, WirelessInfo reports on surveys that indicate the glitch may extend to over 60 percent of iPhones.

"We are still running tests to determine if this issue is really just a bug, but our early results seem to indicate [Apple] may be correct," the publication said. "After an intense series of charging/discharging sessions, the problem batteries on our test iPhones seem to be lasting for longer periods, so this may have been an issue with the batteries requiring some conditioning before they could hold a full charge."

In a related note, Apple's recent release of iTunes 7.3 prevents computers running the software from going into sleep (low power) mode when iPhone is connected via USB.

"This is to make sure iPhone continues to charge overnight," Apple said. "If you want your computer to go into sleep mode when iPhone is connected, you can manually set your computer to sleep. "