If anyone else has this problem — The culprit appears to be a nss library patch recently pushed to address CVE-2014-1568, the remedy was a quick apache restart.
The article if you wish to read further:
http://community.developer.authorize.net/t5/Integration-and-Testing/SSL-Certificate-Problem-Another-Authorize-net-Outage/td-p/47575
Ahh – gotcha. Thanks anyway.
