"City safety" problem?

[DaveJP999]

Yesterday my XC40 MY19 decided to slam on the brakes and stop. I’ve had instances of slight judders when turning corners and the system picks something (usually on the near side) like a car parked off road but yesterday I was travelling in light traffic on a B road when it suddenly slapped on the anchors without warning. I estimate I was travelling 25-28 mph. Was impressed by the stopping power, less impressed with it happening at all. Grateful the lorry that was following had dropped a few hundred years behind.
After it stopped I just accelerated away again. No adverse effects. I noticed The City Safety Activation notification came on the dashboard a few moments later. No repeat in the 50 or so miles since.
Spoke to Volvo on call and they suggested booking into Dealer for check. Not impressed it’s going to cost between £75 and £150 for a diagnosis especially as it’s just had a service.
I’ve also reported the issue via Volvo WhatsApp and it has been escalated so I’ll feedback what they say
I’ve also had issues with speed-signs not being identified correctly (as part of Pilot system)- had these checked out at Dealer but they just say no error, cannot replicate, but they were free under warranty.
I’ve posted here so we can see how often these dangerous aberrations occur.