I do not need a solution (just sharing information)
I have selected SHA2 as the Hash Alg when placing an order for an Extended Validation certificate but it is giving untrusted messages for users with Mac OS X.
After some reasearch I was able to locate information on the Symantec/VeriSign support pages that this is a known issue and Apple CA program is aware of the issue and working on a sollution.
https://knowledge.verisign.com/support/ssl-certifi...
Thought this might help others as I was banging my head against my desk trying to figure out what the issue was.