Verified with 4.3.0-0.nightly-2020-03-11-030217 GCP upi cluster installation with cluster name yy.cn passed. From QE perspective, '.' is supported in cluster name hence moving it to verified state.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2020:0858