Sooo…we did some testing here when it comes to Arnold *.ass file path mapping…
It would be really good to get some example(s) of *.ass file(s) which were having problems path mapping prior to applying the SP16 + code snippet above. We would also need a screenshot of your path mapping settings, so we can validate. Feel free to send this info privately via PM or support@thinkboxsoftware.com (ref this thread)