TL,DR;
So i've figured out it is the curl part of the script that is failing, there are some missing options to curl that causes the download to be wrong.
It seems startup.sh has a parameter of {CURL_OPTS}, but in my case nothing was being used in that parameter, and in closer inspection there are no {CURL_OPTS} specified in this script.
I can work around it by modifying the startup.sh to contain the correct curl options, but any thoughts on this moving forward?