Reverse logistics is messy and unpredictable. A product comes back in a variety of conditions and in unpredictable waves.
Some items arrive in the original box, but most arrive in whatever was available at the time. Sometimes a return includes a return authorization (RA or RMA), but sometimes it does not. Even if it does, what's inside the box might not match what's on the RA/RMA.
These unpredictable details in reverse logistics have created complexity that is difficult for most retailers and consumer brands to handle.