Troubleshoot Ubercart v2 on Drupal 6.37 Duplicating Items In Cart

The last couple days we have started having the problem that items added to the shopping cart are being duplicated. In at least some of the cases, they are showing up as completely separate line items for a 2nd copy of the identical item, which doesn't seem possible. That is, an order showed up like this: Qty 1 of Widget A Qty 1 of Widget B Qty 1 of Widget A Qty 1 of Widget B This should be impossible, as it should have shown like this: Qty 2 of Widget A Qty 2 of Widget B I'm not sure if all of them are showing up that way, or if some of them are actually appearing as a quantity of 2 of an individual item when the customer only wanted a quantity of 1. The administrative staff has been dealing with the orders and editing them to refund people. Also, this is an intermittent problem! Not all orders are experiencing it. I have personally tried to duplicate the problem, but have been unable to. However, at least 3 customers have experienced it over the last few days, so we'd like to get to it sorted out ASAP!