What happened?

Many systems, including those derived from Fedora, do not support fully numeric usernames. An example of one of these limitations can be seen in the problem at shadow-maint/shadow#1339, but I fear it will not be the only one.
As @tolusha points out, CRI-O automatically adds these users, so I strongly recommend changing this logic.

What did you expect to happen?

As a suggestion, you can add a suffix to the number to avoid any problems.

How can we reproduce it (as minimally and precisely as possible)?

NA

Anything else we need to know?

No response

CRI-O and Kubernetes version

NA

OS version

NA

Additional environment details (AWS, VirtualBox, physical, etc.)

NA