In ACP I want to know how many unique visitors have there been in the last week or month.

So I go to ACP > Statistics > Member Visits.

There I have two options: "Last Visit" and "Total Visits".

Now, here are the results (please note that I've filtered by the same groups, same date range and today's date is 9 Juli 2026, so "Last Visit" should give valid results when looking back from today):

Why do they show different results in regard of the unique visitors?
From my understanding "Unique Visitors" in "Total Visits" Should be the same as the number of Users with "Last visited" Date in this date range, shouldn't it?

And if not, which one is correct an why?

Last visit and unique visitors is not the same thing. Last visit would be a count of users whos last visit was that day. Unique visits is how many unique visitors there were on that day, regardless of whether or not its their last visit.

But shouldn't be that the exact same if the end-date of time period is "today" (as above)?

Because, the date of "last visited" can either be within the selected time period (between start date and today), which means the user should be counted in both statistics.
Or "last visited" is before that period, which means, the user is not counted in any of those two statistics.
Thus, it should be the same numbers in that case.

The only case, where "last visited" date would be counted for the "total visits" statistic, but not for the "last visit" statistic would be, when "last visited"-date of a user is after the end date of the selected time period, which is impossible if it's today.

I've assigned to our developers to take a look at and advise.