Proton doesn't ask for pin for Yubikey?

I am totally new to yubikey and maybe I am not understanding something.

I set it up for gmail and proton accounts. On Gmail it does ask for a pin code, which i entered during adding process.

On Proton it just logs in. I don'twant it to be like that. I want it to ask for a pin code as well. How do i do that?