Yes errors are enabled within php.ini. In addition, I purposely added code in the file to add to the error_log, but none of that code is being executed.
In the Network tab of the Web Developer extension in my browser, I do not see a redirect, the last page that shows is the page from Square where the credit card information is added.
I am not entirely convinced it's an error, as when I execute it within Curl, the redirect does happen.
Would you like for me to send you my code via PM?