T46S. User hear the customer when he's on wait

[o.fraiture]

Hello,

I have a weird issue with a t46s. When a customer call and he's putted on wait, we can still hear what the customer say ( the customer hearing the waiting music ).

the software is on 66,86,188,1

Is there anyway to have the firmware to try a reset or update ?

Thanks in advance,

Olivier