Browsing Perl solutions for https://www.codingame.com/ide/puzzle/the-greatest-number I noticed that one of the participants has no nickname (this might be a bug as well, your call).
When starting to look at the solution from the first one, then hitting the arrow on the right to advance, when the solution of that participant is displayed the nickname shown is the one of the previous entry. In the specific case, Experimenter’s solution comes just before, so it seems like Experimenter put two solutions.
The same happens starting from the bottom and “advancing” in reverse order (arrow on the left).