COVID App concern

[Jenasaurus]

My DD has just had a notification that she has to isolate for 5 days as someone she was in contact with on Wednesday has tested positive. She works with children and is literally about 1 minute walking distance from home and that is the only place she went on Wednesday, work and home. Now she has called her Manager and no one else in her team of 8 has received a notification to isolate. Her team basically put their phones in a locker all day while they are working, and she's the only one told to isolate.

How is this possible, she goes nowhere, her walk to work is literally about 40 steps from our home so she wont have passed anyone on route, and she then comes home. The only thing she can think is an Amazon delivery worker may have come in contact dropping off a delivery, but her manager says you need to be in close contact for 5 minutes for it to register.

Its a mystery, None of the children haven been absent, or staff so none of them have tested positive.

Can the app be wrong?

Update,found the source, it was a colleague who had it 40 days ago and because she visited a hospital 3 days ago had to be tested for COVID and it still shows up although shes not actually infected or contagious. Another team member got the same notification. The nursery was short staffed as a resilt and had to close today. The Manager confacted the DFE and was told they could ignore it and so reopening as normal tomorrow. Mystery solved:)

If it was a parent at the nursery, her co workers who were at the nursery on the Wednesday would also have been notified

No they would not have been because you said they put their phones in lockers. The App can’t track YOU, it tracks the phones and if the owner of phone A tests positive, it contacts the owners of any other PHONES that happened to be in range and running the App.