5th gen ipod classic 30gb wont turn off

so i just bought this ipod from my friend. it works great but for whatever reason the ipod doesnt turn off even after i hold the play/pause button for a couple seconds... the only way i have gotten it to turn off is if it is connected to a power source. is there any way to fix this? i have tried restoring the ipod, resetting it on itunes, and holding the menu and center button.... idk what to do anymore😟