Sometimes after a sprint has started, a developer is assigned an urgent bug to fix. In some cases they have already resolved the bug before the PO or SM gets around to adding it to the sprint. There is no way to add it to the sprint (as far as I can see) unless you re-open the bug, add it to the sprint, and the re-resolve it.

This seems like another example of where the new way, adds arbitrary constraints as compared to the classic approach.