Despite Apple’s best intentions, the iPhone OS 3.1.3 firmware update may not have gone as well as the company would have liked.

Per iPodNN, a number of users over on the Apple Discussion Board have reported that issues such as erratic battery life have emerged.

In certain cases, the unit’s battery meter may potentially swing wildly, for instance going from 25 to 7 to 10 percent, then jumping back up to 24%.

Worst-case scenarios may see phones losing hours of power, and even running unusually hot. The v3.1.3 firmware was in part meant to correct battery meter trouble on the iPhone 3GS.

Another major problem involves iTunes playlists, which in some cases are failing to sync properly with the iPod touch. While files will copy over properly, playlists may be empty or simply absent. The glitch is believed to affect only smart playlists, and potentially only those with multiple criteria. Temporary workarounds may include reducing criteria to a single field, and/or deleting and remaking previous playlists.

Apple has yet to formally address or fix either of the cited errors.

If you’ve seen this issue on your end, please let us know.