spree/spree — pull request #3181 by huoxito (2013-06-11 12:09:48+00:00)
Title: No need to call `order.create_proposed_shipments` twice

Shipments are already destroyed and created every time order moves from
address to delivery

As reported in #3169. But I'm not sure how exactly it causes that error. Either way calling `create_proposed_shipments` twice seems like a bad use of current Spree API.