Bug in member list sorting - repeating users

When sorting the member list by posts and looking at the zero posters (requiring a list that is several pages long), you will notice that some members are repeated on multiple pages. This was discovered on phpbb.de and phpbb.com. It seems to be another bug in the sorting of the member list.

I'm also wondering whether the displayed number of members can still be correct due to this problem.

The number of members on phpbb.com is very high, which is why this error is not immediately noticeable. To make it easier to reproduce, you can pre-select a search term that will produce a larger number of pages as result. For example, I searched here with lisa* and angel*, which are common parts of user names.

Attached some screenshots of my results.