The earphones only have accompaniment but no vocals. It can be concluded that the earphones are broken. Most of them are quality problems or the earphones are burned out due to improper use.

Damage to the first unit is relatively common, mostly caused by disconnection of the internal copper wire, damaged plug, or damage to the wire control;

Damage to the second unit is relatively rare, mostly caused by diaphragms, magnets, Damaged solder joints.

You said it can be used after short circuiting, then it is a problem with the wire. If there are no other abnormalities when using it, it should be fine.