Thanks, will keep this in mind, for my next try.

I unpublished it, I don't know how to delete a kata, is there a way?

it would be interesting if at the moment of submitting the kata it would recomend the kata above.

Duplicate indeed! :D my bad.

I think this kata would be better with another name like 'special palindrome' or 'ninja palindrome', given that it contains some exceptions, also as @parabola949 says, try to improve the description.

I'm getting an "Unknown error" when I submit my solution in c#.

This is clever, but I don't think it's fair, because u're using splice anyway.
And the problem specified that u can't use this type of functions.