Comment 9 for bug 1915674

The [homes] section is commented out in the provided smb.conf. I could reproduce it locally by running:

  $ net usershare add games /tmp/X
  net usershare add: share name games is already a valid system user name

again with [homes] commented out (the default). This seems to be a known limitation, I found questions more than 10 years old on the same problem, interestingly often hit because of the 'games' user. This limit is something samba implements, it's not Ubuntu-specific and doesn't appear to be configurable:

https://github.com/samba-team/samba/blob/8b4c6fb7c84e12498a799d155ef6dd439c3fc222/source3/utils/net_usershare.c#L734

I think this is a Wontfix, but I'm marking it as Incomplete for the moment, let's see if we all agree.