Parent project does not have the Release/Iteration as the Child project. But you can see the release when you just edit one item.
Bulk edit is using the global scope to locate the releases, so when scoped to the parent, the release won't be located. The user can change their global scope to the project for the stories to do the bulk edit.
The user has to select the Child project to plan the stories, so that the bulk edit could show the correct release. And in order to see the Feature which belongs to Parent project, User should select the "Parent Projects" option from project picker. Then the user could see the PI from parent project and also could plan all stories under this PI.