Cargo rollover happens for a variety of reasons, at various stages and various places. Customers rely on an official notification from the carrier about the cargo rollover in order for them to take any action.
But only a few carriers seem to notify customers in advance that their cargo is about to be rolled or has been rolled. This especially happens when transhipment is involved and catches many customers by surprise and upsets their production or sales plans.
If you are the customer, it is possible to recognize when your cargo is on the verge of being rolled, assuming it hasn’t already been rolled.