Users who have both primary and secondary membership are printed twice

[gebn]

First, members scans passwd looking for primary members, and prints them. Then it retrieves the group from groups and prints all secondary members.

If a user has a given group as their primary group, and are also secondary members of the same group, their username will be printed twice.

Is this a bug or a feature? I'd argue a bug: being a member twice makes no difference to how membership functions. However, it is a breaking change.