After iPod touchscreen replacement some touches/gestures don't work

I replaced the touchscreen on an iPod 4th gen and the new screens touch functions are off slightly. After then restoring the iPod and with the latest software problem remains. I have rechecked/cleaned all the connections inside. The screen unlocks fine, swipes and application icon presses are okay. Some submenu icons will refuse to press, scrolling/pinching/zooming generally fail and are interpreted as a sequence of clicks. We already have another screen on order. First time working with iPods. Any suggestions as to what might be the trouble?