Volume button "stuck"

My friends Xiaomi (Redmi note 10) is acting up a bit, it acts as if the volume down button is being pressed constantly, even though he's not pressing it and the button itself doesn't appear stuck physically. When restarting it even goes to fastboot. He told me he doesn't want to wipe the phone, and I don't even think that would help. I'm going to open the phone in a few days when the glue I bought gets here, do you guys have any tips as to what could be happening internally? could it be a system problem or am I right to think it's an electrical one?