ePro Persistent Cart sporadically shows zero lines on the icon even when not empty

Our configuration is set to land on the Requisition Defaults page upon clicking the Create Requisition tile. We are finding that at times, when creating (or editing) a requisition, if the user goes back to the req defaults after adding items to the cart, when they click "Done" to get back to the lines, they are brought to the Create Requisition page where the lines already added don't display, and the Cart icon shows a zero next to it (as if the cart is empty). However, clicking the cart icon (although it shows zero) displays the cart summary, with the