[arch-general] Different outputs for 'groups' and 'groups user'

[riveravaldez]

Hi, not sure if this is the right place to ask this, let me know if it's not.

Maybe this is normal, but couldn't clarify it by reading the Arch Wiki [1]:

[user at arch ~]$ whoami
user
[user at arch ~]$ groups
sys lp wheel ftp uucp log rfkill http games audio users user
[user at arch ~]$ groups user
sys lp wheel ftp uucp log rfkill http games audio users realtime user

Why different outputs?
Is it normal and with no issues?
Should I do something?

Thanks a lot!

[1] https://wiki.archlinux.org/index.php/Users_and_groups#Group_management