Firewalld Adding Interfaces to a Zone Issue

Hi guys,
as always, thanks for helping with my issues.

I have been studying firewalld lately, here is an issue i have not been able to figure out.

1. All interfaces by default are added to the default zone. In my case, the "public" zone is default.
2. I have three interfaces ens32 ens33 and ens34, all assigned to the public zone.
3. I removed ens34 from public zone

' firewal-cmd --permanent --zone=public --remove-interface=ens34'
success

4. Now I add ens34 to the "internal' zone
   ' firewall-cmd --permanent --zone=internal --add-interface=ens34'
   success

5 . Each time i reboot the server or i restart firewalld, ens34 gets assigned back to the "public " zone.

What I am doing wrong here?

Thanks All

Arrey