Issue initializing postgreSQL 13 on CentOS 7 docker

I am running postgreSQL 13 server/client successfully on my workstation but am having problems setting it up in a docker container, both running CentOS 7. I have previously run postgreSQL 9.6 successfully in docker but right now I am unable to initialize the database under pg 13. For some reason the following:

postgresql-13-setup initdb -E 'UTF8'

fails with:

systemctl: invalid option -- 'E'

The equivalent to the above worked fine when running pg 9.6.

I can add that:

postgresql-13-setup initdb

works fine but then the databases default to SQL ASCII which is not OK.

There seems to be some issue with Fedora and later pg versions with respect to locale settings as seen in:

https://bugzilla.redhat.com/show_bug.cgi?id=1872511

but I am not certain the same issue applies to my situation. The file glibc-langpack-en does not seem available for CentOS 7 although my solution might also rely on fixing the locale situation. Anyway, where would I file a bug? RedHat or here?

I'll be happy to supply more information as needed.