;-)

I've checked out the issue: my validate function call digitsProduct instead of itself when it performs recursion.
Now it's fixed. Many thanks ;-)

If you are surely that you meet the problem in random tests, please paste your code here and mark it as having spoiler content. Let me check the random tests using your code. thanks ;-)

Which language? I guess you are using JS, but I test input 6 in JS, it expect the result 6, insted of 23.

EDIT: I'm sure that my validate function expected 1 digit result, because the first line in my code is if(product<10) return product?product:10.
Same result in c#.

kata not ask for at least two digits, the goal is a smallest positive integer. In the example tests, two testcases test for 1 digit(1 expected 1, 5 expected 5)