Problems when using A/C charger?

[smorloc]

I have an iPod Touch 32GB. When charging using a third party A/C charging adapter, the Touch behaves differently, not responding to screen touches. While charging, with the screen off and playing an audiobook, if I double click the 'home' key, the 'slide to unlock' screen comes up with the music controls at the top of the screen. Most of the time I can click on the unlock slider or the media controls and they will highlight however they will not perform their action. To solve the problem I typically will click the power button & try again. Eventually it will start responding to my screen taps again. Is this unusual behavior when the Touch is charging?

Steve

[Salamis]

Same with my iPod. When it's charging from the wall charger, if I slide to unlock the bar slides about halfway and bounces back to the left side. So I can't unlock it when I'm charging it.