When I remember correctly does /lp group default listmembers not show all members in that group (Because of code or whatever).
If that's still true should there be a note/message about this when using this exact command, to inform tha player about this fact and reduce confusion about why some players aren't displayed within that group's listed members.

Yeah this confuses so many people.

And I think that is should show at least online players (that are in default).