We have a very customized vm shopping cart site, not using SSL, but using Authorize.net for payment processing (actually just for authorization).
About every 10 orders we get a 'duplicate' order, where the order is placed twice about 1-3 minutes after the other (the customer is not doing this).
What can we do to fix? We are not ready to upgrade just yet, will be doing that in Jan 2016.
site: http://www.allinonesuppliers.com
I seem to remember a while back there was some issues with duplicate orders.. ( or did I dream this?)
Various code was done to prevent double clicks on checkout etc.. but VM2.6. is now on version 20 so .....