Stress Fracture to side panels around windows

We are looking at exchanging our 2015 Nuevo EK for one registered in March 2020 with only 8000 miles.

When did the stress fracture issue first manifest itself please?

I was told by Auto Sleepers customer service that this problem started on the 2018/2019 models when a redesign was made. Our 2019 Burton suffered this fault in 2021, and went in to be repaired and strengthened in March 2022. Our first trip away was to France and 2 days into our holiday the crack appeared again.
On our return to the UK we took it back to AS and it was booked in again but due to the backlog of failure incidents
There is a wait list. It will go into AS next month. The window corner  repairs are now being sent out to a professional body shop and will have a lifetime guarrantee  when completed.