$(document).on('ChangeCurrency', function () is executed 2 times?

Question

JavaScript

Good health, connoisseurs!
I don’t understand why $(document).on('ChangeCurrency', function () is executed 2 times?
Inside there is a variable waiting, because there is a delay in getting 1 variable
if(One!== undefined && Two !== undefined){
}

As a result, the code works, but the console writes 2 results each, what did you do wrong?