Here's a tricky one for Ubercart 7.x-3.4.
I am getting occasional reports from customers that they fill out the information on the Checkout page and click the "Review Order" button, but the page just reloads, returning them to the checkout page.
They get no error messages, and there's nothing in the log. If I call them and walk them through it, it works fine every time, so it's some sort of intermittent problem.
These customers (usually anonymous) do have abandoned carts that contain their shipping and billing information, which appears to be correct.
So, I don't even know where to start troubleshooting.
My current wild guess is that it's some sort of communications glitch with Authorize.net, but that's just a guess.
Has anyone heard of this one before? The vast majority of customers don't report any problems.