Not being able to receive messages except on one device isn't a minor inconvenience.
To fix this, you either need to authorize each device (and web browser) from another device that's logged in, or the central authority holds your keys.
I run WhatsApp concurrently on two phones and receive all messages on both devices. But generally speaking this is where we disagree - requiring all devices to be authorised by me is feature not a bug as far as I'm concerned.
To fix this, you either need to authorize each device (and web browser) from another device that's logged in, or the central authority holds your keys.