Jira CSV import throws "Fatal Error: Sub-Task Issue cannot be null"

[Jessica Zhang]

Jira CSV import throws "Fatal Error: Sub-Task Issue cannot be null" even though validator passes.

Importing via external system import is successful; however, doesn't trigger JIRA automation rule because JIRA doesn't trigger task creation event.

sample csv:

Epic Link	Issue Type	Issue ID	Parent ID
Project Freeze	Task	10
Project Freeze	Sub-Task	11	10

[Kristin Lyons]

Have you tried to import the parent issues first and then the sub-tasks?