Competition rules. The game rules are not stated anywhere in the game, but your default rules, which are unfair to newcomers to Drivendata.
Two test sets. Since all submissions have results on the two validation sets A and B, the two test sets have the same weight, and the B set cannot achieve the result of preventing overfitting as same as A. On the contrary, according to result B, it is more like overfitting.
The distribution gap between the two test sets A and B. I feel that the organizer has not done any pre-experiments, and the data set is divided without considering the data distribution, which is irresponsible to any participant.
I hope the organizers can reconsider the unfairness and unreasonableness in the competition.
Hope there is an explanation before the results are announced.