Checklists not correctly imported from backup

[really-just-a-tech]

Describe the bug When importing a backup, all checklist items will be converted to normal tasks.

To Reproduce

1. Create a task with checklist items
2. Go to Preferences > General > Export database and save your backup somewhere
3. Delete all Planner data
4. Import the previously saved backup
5. See that the checklist items are now separate tasks

Expected behavior Checklist items should be imported as checklist items.

Screenshots Before backup: After backup and import:

Desktop:

• OS and DE: Fedora 33 with GNOME 3.38.5
• Version 2.6.9 (Flatpak)

Additional context When making a second backup after the import, you can see that the "parent_id" is 0 instead of the id of the task it belongs to. It is correct in the first backup, so the problem lies with the import.