As @B4B already pointed out, this kata is a duplicate of https://www.codewars.com/kata/do-not-loose-at-tic-tac-toe. But that was 3 years ago and this kata has not been unpublished still now, so I was wondering what is the future of this kata, would it be unpublished eventually? Or remain in beta forever?

I also faced the same issue. However between 307 and 317, 311 is also a prime number so 307 and 317 are not perfect 10 gap prime numbers. The question does mention about this issue. I will be putting it here so that you can understand it better.
"gap(6,100,110) --> nil or {0, 0} or ... : between 100 and 110 we have 101, 103, 107, 109 but 101-107 is not a 6-gap because there is 103 in between and 103-109 is not a 6-gap because there is 107 in between."(Taken from the original question).
So the kata expects you to return 2 primes with the gap 'g' such that there are no primes among the numbers between those numbers.