Power button not working.

Hi, my girls phone recently started doing this weird thing where it appears that the power button is being pressed down even though the button isn't being press or stuck in the pressed position. I order a replacement part, the daughter board that has the power button on it and after I did it appeared to be working correctly. Then about a day or so later the power button stopped working all together. Not sure what the issue might be other than a bad part but I find it strange that it was working and then just went out all together.