Some Bluetooth headset will set to SBC mode before shipment.
Such as Sony MDR-ZX770DC, MDR-ZX750BN, MDR-ZX770BT, etc. Below image is a screen shot of Guide Start Guide for Sony headphones.
In this case, we suggest customer to contact the manufacturer.
Any questions, please feel free to let us know.
How to change the sound quality mode of music playback on Sony headphone, please refer below link -