Are replacement on off, volume cables commonly defective.

I have 2 4th gen ipod touches I replaced vol and on off cable in both, one had a damaged cable the other just because it was already apart and was well used. the first cables I ordered were defective they had no click on the volume down switch I did not discover until I had installed one of them. I installed 2 new ones with operating switches, volume was stuck on high on both the on screen volume control would adjust the volume but as soon as you removed your finger it returned to high. Later the on screen started working for no apparent reason. The on off switch will allow a reset for restore and nothing else. ground issue? HELP! Thanks