Headset remote control not working after OxygenOS 2.1 update (Xiaomi Piston 2)

Hi,

just found out my xiaomi pistons 2 headset remote control is not working after the 2.1 update (they worked before),
I tested a pistons 3 headset which is still working, can anyone tell if an easy workaround can fix this ?
Btw is there an official way to report a bug to oneplus or just wait for someone to have a look in their forums ?

Thanks

Xiaomi Piston 3,why it's so hot?

I found Xiaomi Piston 3 is very hot ,ant it's on a hot sale on those online shopping website,such as amazon,tinydeal,banggood.Why is't so hot?Because its brand or the product'quality or something else like piston 2?