Sorry I cannot reproduce the issue. I just updated an instances started from the same ami in eu-central-1.

# zypper ref
Refreshing service 'cloud_update'.
Repository 'SLE-Module-Adv-Systems-Management12-Pool' is up to date.
Repository 'SLE-Module-Adv-Systems-Management12-Updates' is up to date.
Repository 'SLE-Module-Containers12-Pool' is up to date.
Repository 'SLE-Module-Containers12-Updates' is up to date.
Repository 'SLE-Module-HPC12-Pool' is up to date.
Repository 'SLE-Module-HPC12-Updates' is up to date.
Repository 'SLE-Module-Legacy12-Pool' is up to date.
Repository 'SLE-Module-Legacy12-Updates' is up to date.
Repository 'SLE-Module-Public-Cloud12-Pool' is up to date.
Repository 'SLE-Module-Public-Cloud12-Updates' is up to date.
Repository 'SLE-Module-Toolchain12-Pool' is up to date.
Repository 'SLE-Module-Toolchain12-Updates' is up to date.
Repository 'SLE-Module-Web-Scripting12-Pool' is up to date.
Repository 'SLE-Module-Web-Scripting12-Updates' is up to date.
Repository 'SLE-SDK12-SP2-Pool' is up to date.
Repository 'SLE-SDK12-SP2-Updates' is up to date.
Repository 'SLES12-SP2-Pool' is up to date.
Repository 'SLES12-SP2-Updates' is up to date.
All repositories have been refreshed.
ip-172-31-10-167:~ # time zypper ref
Refreshing service 'cloud_update'.
Repository 'SLE-Module-Adv-Systems-Management12-Pool' is up to date.
Repository 'SLE-Module-Adv-Systems-Management12-Updates' is up to date.
Repository 'SLE-Module-Containers12-Pool' is up to date.
Repository 'SLE-Module-Containers12-Updates' is up to date.
Repository 'SLE-Module-HPC12-Pool' is up to date.
Repository 'SLE-Module-HPC12-Updates' is up to date.
Repository 'SLE-Module-Legacy12-Pool' is up to date.
Repository 'SLE-Module-Legacy12-Updates' is up to date.
Repository 'SLE-Module-Public-Cloud12-Pool' is up to date.
Repository 'SLE-Module-Public-Cloud12-Updates' is up to date.
Repository 'SLE-Module-Toolchain12-Pool' is up to date.
Repository 'SLE-Module-Toolchain12-Updates' is up to date.
Repository 'SLE-Module-Web-Scripting12-Pool' is up to date.
Repository 'SLE-Module-Web-Scripting12-Updates' is up to date.
Repository 'SLE-SDK12-SP2-Pool' is up to date.
Repository 'SLE-SDK12-SP2-Updates' is up to date.
Repository 'SLES12-SP2-Pool' is up to date.
Repository 'SLES12-SP2-Updates' is up to date.
All repositories have been refreshed.

real 0m0.398s
user 0m0.246s
sys 0m0.036s


What server are you pointing to?

grep susecloud /etc/hosts ?