61Design

Have discovered the issue.
The admin order page allowed to input quantities smaller than the defined step value. So for example, a customer might order 0.5kg of a product, then the admins would update the quantity to 0.518 and save the order once it was processed.
Previously this used to work OK, but it appears that the plugin is now preventing the orders from being saved.
Rather than generating a visible error when attempting to update the order, the plugin just errors out and prevents the form from being submitted at all.
This really needs to have a visual warning when admins update orders with an incorrect step quantity.