Hello stephenw10 ,
I wanted to wait to be sure but I no longer have any disconnection from this IPsec bridge.
When I reduced the delay to 1 hour, I no longer had this problem, but therefore no more logs :)
So I postponed the 8 hour delay to have this cut again, but it no longer cuts!
So too bad for the explanation, I'll look at the logs if it comes back.
A big thank you to you for your answers <3