Thy should have just upgraded the kernel to a fixed one, which definitely does not require to upgrade the whole distribution. Also if they are using Kubernetes

Thy should have just upgraded the kernel to a fixed one, which definitely does not require to upgrade the whole distribution. Also if they are using Kubernetes normally there is no reason to not upgrade the whole distribution as well, since only Kubernetes will be running on it, and of course that's widely tested (the containers each choose their own distribution, only the kernel is shared).