The "past members" list (which is available only to premium groups, in case anyone reading this doesn't see theirs), as it currently exists, is not really a list of past members. It is really a list of *actions* of removal/leaving/banning. Each time a member leaves, is removed, or is banned, another row is added to the list for that member, with the date of that particular action displayed in the date column (which is labelled "left") and the "reason" column giving the action - either "left," "removed," or "banned."
I think, and think the majority of people think, of a "list of x's" as containing one row for each x. In this case, the x's are actions, not members, at least as currently implemented.
(BTW, and this is a separate but related issue: if you sort the list by, say, display name, the removal/left/banned actions for any particular member with multiple actions appear in a seemingly random order with respect to the dates of the actions. At least, I have yet to discern the pattern to it.)
To make the list more intuitive, I think you could either keep the contents as is but rename the list to reflect the fact that it's a list of actions, not of members;
or keep the name the same but display only the most recent left/removed/banned action for each member. This would be analogous to the banned list, where each banned member gets only one row no matter how many times they were banned. (The rest can be found in the member's activity history anyway, and it doesn't seem necessary to display every such action in the list.)
Those are just off the top of my head. I think the second idea is probably preferable.
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