Digitizer works with one iPod but not the other. Water Damage?

I have an iPod Nano 7th Generation that the digitizer is unresponsive. The LCD screen, charging port, power button, volume buttons, etc. all work fine. I took the digitizer out and placed it in another iPod Nano and it works fine. So my question is: Is this a sign of water damage or is there something software related? I have repaired 6-7 of these Nano's before and have not ran across this issue. Any answers are much appreciated. The history is unknown on this ipod since it was purchased on Ebay. Thanks in advance.