White light only indicates after 100% charging which takes time. Let the wireless bullets Z stay connected with the adaptor, it will indicate white light.
I also faced this, while on video call if there is an incoming call accepted, audio diverted to device. May be it is devised to function like this. It's not a issue i think, for further clarification you should ask support -
https://www.oneplus.com/global/support/contact
Last edited: Dec 30, 2020