*Might* be able to fix it by changing whatever IC it's using for FM radio with an original IC.
eg, it might use a FM radio IC that is a china clone of a proper brand IC. That stuff happens a lot in china.
However, thinking about it more, i suspect what they are likely doing is using a cheap combination bluetooth+FM radio IC to save money.
Basically a BLE chip with a bad FM radio hacked onto the radio section.
You wont be able to change that as the BLE radio comms will be very integrated with the OS/MCU.
You could perhaps open it up and make sure the antenna section has coax to the external antenna socket. Maybe it's just wires?
But best option is probably just to buy a new different $20 one that doesn't have this issue.
It will likely have some other different issue though
