double type blackwidow mini

All keys? or specific ones?

all keys broo 

yelllow swich

1st I’d try connecting different USB cable (data capable!).

2nd - test it on another PC without Synapse installed.

I triedthe error also occurs when connecting it to the play 5

using it on the play shouldn't have any kind of software interference that windows or synapse could give, right?

Try other cable then.

even changing the cable, it doesn't work, double buttons always, even wifi or bt, it doesn't work

So I’d contact Razer Support and RMA it if you still have valid warranty: https://mysupport.razer.com/app/warranty-support/

but is it a defect only of the version with yellow keys or does the version with green keys also have the same or similar defect?

but is it a defect only of the version with yellow keys or does the version with green keys also have the same or similar defect?

I’d not link this issue with switches if all behave the same - I’d assume keyboard PCB problem.

Also you can try updating firmware (unless you’re on the latest version): https://mysupport.razer.com/app/answers/detail/a_id/6317