The coronavirus Test and Trace app for England and Wales has been updated after users reported confusion from a notification suggesting they may have been exposed to the virus.
Some using the contact tracing app were left panicked after receiving the so-called "phantom alert", with reports that the notification would disappear when tapped on and no further information would be displayed.
The message read: "Possible Covid-19 exposure. Someone you were near reported having Covid-19. Exposure date, duration and signal strength have been saved."
The Department of Health and Social Care (DHSC) placed the blame with Apple and Google.
The DHSC said the particular alert was a default privacy notification from the companies who created the underlying technology, to alert people that the app is sharing information with the system.
To ease concerns, however, an update to the app will provide a follow-up message, saying: "Covid-19 Exposure Check Complete. Don’t worry, we have assessed your risk and there is no need to take action at this time."
It will advise users to "continue to stay alert" and adhere to social distancing measures.
The DHSC said important messages from the NHS Covid-19 app will always be visible to the user when they open the app, even if they miss the notification.
"NHS Covid-19 app users only need to self-isolate if they get a notification directly from the app advising them to do so," a spokesperson said.
It comes after a recent climbdown on the app's check-in scanning - which people can use when visiting venues such as restaurants and pubs.
Despite initially being heralded as an important aid to contact tracing efforts, the government later admitted it does not expect to send out alerts frequently from the QR code feature.
Since launching on September 24, the app has been downloaded more than 16 million times but suffered many set backs and delays before getting up and running.
Scotland and Northern Ireland have their own contact tracing apps which use the same underlying system developed by Apple and Google.