Why Azure app service plan restart recently?

I have a P1v2 type appservice plan instance.
It runs 3-4 nodejs application services in a containerized environment.
These application services have been completely error free for a whole year, the metrics don’t show anything that would overload them, there are no application side errors either.
The appservice plan metrics are also fine.

But lately, once or twice a week I get flooded with alerts because the appservice plan restarts, so all 3-4 appservices too.
And the container startup time is around 3-4 minutes.
And in the meantime the CPU usage increases, plus there are other alerts.

Anyone have any idea what could be the reason for the restarts?

Source: Docker Questions