NHS ping confusions

[Afonavon]

Can anyone shed some light on something regarding the ping I received today. It states that I have been a contact of someone who has tested positive for Covid. All fine so far,

However the app is telling me to isolate for 7 days, not the full 10. I have Googled and Googled, but can’t find any explanation why I have only been asked to isolate for 7days And not the full 10.

Does anyone cleverer than me, have any idea why this is?

It’s 10 days since you were in contact with them.

The contact was three days ago?

Your 10 days starts from the day of contact so if its taken 3 days for the system to ping you you're down to 7 days now - I think

It’s 10days from the date of the contact, not the date it pings you. So presumably your contact was 3 days ago and you only 7 days of the 10day isolation period left.

I had one recently for five days.
I can only think Test and Trace didn't pick up the contact until I got pinged. (Maybe because the person took their time getting a test?)

One of my colleagues had to isolate for 2 days as it took so long to trace her. Waste of time as she would have already passed it on by then!

Dd had to isolate for a few hours! Ran out at midnight - got the alert at 6pm!

Ah thank you, that makes sense.

We’re isolating at the moment, a 6 day one. We had contact last Friday but didn’t get pinged until Tuesday morning.

I got pinged for 6 days, but hadn't been anywhere 4 days previously that would have resulted in a 6 day isolation period.