Cancelling the hung export or virtual standby will release the agent to allow for snapshot, replication and rollup operations, however the symptom will likely re-occur at next export task.
This is a Rapid Recovery driver defect. The defect was fixed in Rapid Recovery 188.8.131.525 which is available for download here. If you are running an earlier version and for some reason you cannot upgrade (i.e. your replication is handled by a third party that did not upgrade your target core yet), a patch can be provided upon contacting support.