NHS Covid-19 app: Why does coronavirus contact-tracing tool keep giving me two notifications at same time?

The NHS Covid-19 app is continuing to confuse users who are being sent a flurry of notifications.The app now sends two notifications each time a potential exposure is found, even if it is then checked and found to be not significant enough to require action.The initial problems arrived when users kept receiving a message that they had been subject to a “possible Covid-19 exposure”.