Hey Dylan,

It looks like it's a weird part of how that API works. According to the jQuery docs:

The callback is fired once the script has been loaded but not necessarily executed.

Scripts are included and run by referencing the file name:

https://api.jquery.com/jquery.getscript/

It might be that your callback function is executing before the script has executed in some instances but not others. It looks like it might work if you replace your syntax with this, per this stack overflow answer:

https://stackoverflow.com/questions/14565365/jquery-getscript-callback-when-script-is-fully-loaded-and-executed

$(document).ready(function () {
    $.getScript('https://cdnjs.cloudflare.com/ajax/libs/jquery.mask/1.14.16/jquery.mask.min.js').done(function (script, textStatus) {
        $(".ssn input").mask("999-99-9999"); //SSN Mask
        $(".phone input").mask("(999) 999-9999"); //Phone Number Mask
        $(".date input").mask("99/99/9999"); //Date Mask
    });
});

If that doesn't work, you could wrap your code in a half second time out. It's ugly but if you don't mind your page not being optimized it then it's probably the simplest way to get it working:

$(document).ready(function () {
    $.getScript('https://cdnjs.cloudflare.com/ajax/libs/jquery.mask/1.14.16/jquery.mask.min.js').done(function (script, textStatus) {
        setTimeout(function() {
            $(".ssn input").mask("999-99-9999"); //SSN Mask
            $(".phone input").mask("(999) 999-9999"); //Phone Number Mask
            $(".date input").mask("99/99/9999"); //Date Mask
        }, 500) //500 is the time in miliseconds that the timeout should wait to execute the code. 500 is half a second
    });
});