GCP overriding iptables rules in centOS

I created a CentOS machine from base image that can be found in GCP. After powering on I looked at the iptables rule, seems like everything is on

I removed all the firewall rules and chained ones as well and created some firewall rules and saved them. When I restarted the machine all the newly created firewall rules were gone and the default ones came online. Not sure if GCP overrides firewall rules after reboot?

Enabled VPC firewall rules are always enforced, protecting your instances regardless of their configuration and operating system, even if they have not started up.