Ok...I must have just disabled the cart module (mod_cart) and not the entire cart.
I guess I don't have the option of NOT using the cart because we have a total of 16 events, and then another 15 classes and items they can purchase through the DT Register. UGH!
I upgraded to 2.7.8 because I saw that multiple cart items was a fix...I hope I can get a response from my support ticket. It was sent Friday.
I know a few of you were requesting updates on this issue...
I heard back on my support ticket this morning. They said that testing on their end was fine but they saw that my site was having problems with the cart. They asked for my FTP information so they could go in and take a look.
Haven't heard anything back and that was first thing this morning but hoping to hear something tonight! Will let you know!
Sorted this out through a ticket, but for others reading this... it was not a DT Register problem, which we figured from the beginning.
The cart dropping issue WAS fixed with 2.7.8. No one else has reported problems since them outside of this one ticket. The problem ended up being a PHP restriction of memory_limit which was set VERY low. Thanks.
dyvel - haven't had any other reports of this for a while. If you believe an issue remains, please submit a ticket with exact steps of how it can be replicated on your site. Might also check your site and disable any cache (in joomla, plugins, template, etc) that is setup as it could be tripping things up.