I cannot reproduce this problem with your current Python solution either.

Yes, it seems to me that negative numbers are tested.

In what language? Negative numbers should be tested, but without knowing the language, I do not know where to check.

Your solution passes some thests and then either crashes, or times out. It is difficult to tell without knowiing your code, or the language you are attempting. I cannot reproduce this problem with your current C# solution.

I did not claim that understanding the task was common sense, everyone can make mistakes. I misunderstand or miss things in descriptions often, too, and only realize it when I submit my code and see that it does not pass the tests.

What I meant by common sense, as I wrote, and as explainedhere, was that when you think you have found a really big mistake, especially in a kata with so many completions (and 38,500 completions is massive), you should stop and think:
Did I understand the task correctly ? Am I solving the right problem ? Did I miss something in the description ?

Only after double checking everything, scrolling down the discourse page to see if there have been similar remarks / reports in the past, you should open an issue. Issues should not be opened lightly, as:

• they create more work for the volunteers who curate Codewars content, who will check the issue report, try to reproduce / analyze it, and possibly submit a patch
• accumulating bogus issues discourage people from trying a kata, and encourage newbies to blame the tests for their own mistakes, thereby opening yet more bogus issues.

I did try to explain the mistake in your logic, too, but you kept focused on your own interpretation of the task instead of on what the description explains.

and stop raising issues when you do not understand something in a kata; it is rude. an issue implies there is a serious problem with a kata, that other regular users (volunteers) will have to analyze, debug and fix. when you are confused, ask a question.

How do you get from digit 9 to digit 3? It's not adjacent. Everything seems consistent with description, unless you're misunderstanding it.

You are misunderstanding this sentence:

, it is possible that each of the digits he saw could actually be another adjacent digit

it means that any 1 could actually be a 1, a 4 (bottom vertical from 1), or a 2 (right horizontal from 1). So 24 is a valid possibility for 11.

Please exercise some common sense when raising issues. This kata has nearly 40,000 completions. If there was such a glaring mistake in the tests it would have been already noticed and/or fixed by now.

If you see that error message, then it isn't returning 1.

Unfortunately, tasks which are meant to reimplement a built in are not really good Codewars kata. Restrictions are very easy to work around, and difficult to enforce.