I figured out the problem. Previously you allowed "x" and "y" to be either strings or integers. However, you recently changed something and made it so only integers, not strings (even if those strings happened to be integers), can be used. So in my case the '26' and '23' were strings and thus were throwing an error.
If anyone else encounters this it can be resolved using parseInt(). Artem, you may want to consider reverting to the previous behavior by using 'parseInt' when 'typeof' returns string, or by switching from whatever check you're using (I'm guessing a typeof number type thing) to the Number.isInteger check.
