If I have opened whatsapp web in a tab, and I am working in another tab and receive a message on whatsapp, opera suddenly stops working and closes. This does not only happen while using whatsapp web, but also if I set a timer (www.tomato-timer.com as far as i know) and it goes off. This does also happen when I have opened whatsapp or the timer in another window.
I use Opera version 56.0.3051.52