they keep their associations. It's a little bit strange then - the Epic is in the new project, the associated story in the old one.
You have to move the story also. But moving a story moves their task also.
(I can't add the 'at Jack Brickey'-tag - invalid HTML...)
For what it's worth, as of Jan 2021 I found that Jira Cloud will prompt you to include child stories when moving an epic from one project to another. See screenshot below.
The result is that the epic and child stories are migrated all into the new project with the parent-child relationships intact.
Hey there Cloud Community members! We’re excited to give you the first glimpse of the new home for business teams on Jira — Jira Work Management. Jira Work Management is the next generation of J...
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