Eu verifiquei e é necessário um comportamento pretendido.
Kubernetes controls the health check and configures it from data inside the kubernetes cluster. Kubernetes does not see any changes made to the health check via gcloud.
Por isso, acho normal que ele seja verificado e que qualquer modificação seja revertida.
A solução para usar readinessProbe em seu lugar.
Por favor, dê uma olhada também para this :
Health checks
Currently, all service backends must satisfy either of the following requirements to pass the HTTP(S) health checks sent to it from the GCE loadbalancer:
Respond with a 200 on '/'. The content does not matter.
Expose an arbitrary URL as a readiness probe on the pods backing the Service.
The Ingress controller looks for a compatible readiness probe first, if it finds one, it adopts it as the GCE loadbalancer's HTTP(S) health check. If there's no readiness probe, or the readiness probe requires special HTTP headers, the Ingress controller points the GCE loadbalancer's HTTP health check at '/'.