At the moment, when you replace the exam for a resource, it's only used in attempts subsequently created.
If there's a bug in the old exam and you upload a fixed version, it should be possible to force existing attempts to use it.
There should be a checkbox on the replace package form labelled "This is a safe replacement for the current exam package". If ticked, all attempts using the old exam will be updated to use the new exam.
At the moment, when you replace the exam for a resource, it's only used in attempts subsequently created.
If there's a bug in the old exam and you upload a fixed version, it should be possible to force existing attempts to use it.
There should be a checkbox on the replace package form labelled "This is a safe replacement for the current exam package". If ticked, all attempts using the old exam will be updated to use the new exam.